PTO Installation And Applications Instruction{1165} Caterpillar

Safety

General Hazard Information

Do not operate or work on the engine and/or PTO unless you have read and understand the instructions in this Manual. Failure to follow the instructions could result in personal injury.

Attach a SEHS7332, DO NOT OPERATE tag or similar warning tag to the start switch or PTO controls before performing maintenance or repairing the engine and/or PTO controls. Do not allow unauthorized personnel on, around or in the vehicle when maintenance or repair is being performed.

Do not start or attempt to start the engine, or uses any of the controls, if there is a warning tag attached to the start switch or PTO controls.

Do not attempt repairs you do not understand, refer to your dealer.

Start the engine only from the operator's station (cab). Never short across the starting motor terminals or the batteries. This could bypass the engine neutral start system as well as damage the engine electronics.

Never attempt adjustments or repairs while the engine is running unless otherwise specified in this Manual. Guards should be in place whenever repairs are performed.

Do not climb on or jump off of the vehicle when performing repairs, use an adequate ladder.

Do not disable or bypass automatic alarm or shutdown circuits. They are provided to prevent personal injury and engine damage. Make provisions for shutting off the fuel supply to stop the engine in the event of an engine overspeed.

If Engine Monitoring is programmed to Derate or Shutdown, and one of the monitored conditions is exceeded, the engine will Derate or Shutdown. This should be considered especially if shutting down the engine while in PTO operation could present a problem for the vehicle or risk to the operator.

If PTO Shutdown Time is programmed, the timer will become active when PTO is switched ON and can not be overridden. When the elapsed time equals the programmed value the engine will shutdown regardless of load.

If the PTO Vehicle Speed Limit parameter is used to avoid vehicle speed circuit disconnection because the PTO is transmission driven, parking brake switch and neutral switch interlocks must be used in the PTO On/Off Switch circuit.

For specific topics regarding proper operator instructions and information for your truck configuration, refer to "Recommended Information for Driver/PTO Operators" on page 7 in this Manual. Refer to the Operation & Maintenance Manual for your truck engine for additional safety and hazard information.

Welding on A Vehicle Equipped with a C-10, C-12 or 3406E Engine

Before welding on a vehicle equipped with an electronic engine, the following precautions should be observed.

1) Disconnect all cables connected to the vehicle batteries.

2) Disconnect both ECM Connectors (Vehicle Harness - J1/P1 and Engine Harness - J2/P2).

3) Do not use the ECM or Engine Ground Stud for grounding of the welder.

4) Locate the welding probes as close as possible to the welding area.

Advantages of "Dedicated PTO"

Background

The C-10, C-12, & 3406E Truck Engine Personality Modules provide several options to enhance applications requiring control of engine speed for vocational applications. Applications enhanced with the these options include Cement Mixers, Refuse Packers, Bulk Haulers, Utility Trucks, Fire Trucks, etc, or an application requiring control of engine rpm for operating specialized equipment. Nine "Dedicated PTO" parameters, three inputs, and one output are available. Using these features, combined with past features, provide a significant increase in engine capability and usage for these special applications.

Compared to mechanically controlled engines, the features available with the electronically controlled C-10, C-12, & 3406E Truck Engines eliminate mechanical control cables, air cylinders, electric solenoids, and associated linkages and connections. Compared to early electronically controlled engines, the features available with the C-10, C-12, & 3406E Truck Engines provide a cleaner installation and leave the cab throttle position sensor and cruise switches untouched for over-the-road use.

* Features

* Reduces or eliminates alteration of cab wiring.

* Unnecessary to alter cab throttle position system to disable cab throttle/accelerator pedal.

* One Speed Control (Programmed low idle to PTO preset Set Speed) for engine rpm with one circuit.

* Two Speed Control (Programmed low idle, PTO preset Set Speed, and PTO Top Engine Limit) with three circuits.

* Remote second Throttle Position Sensor input for variable speed engine rpm control.

* PTO Switch On Lamp to indicate engine is in Dedicated PTO Mode.

* Customer Programmable Parameter Options

* PTO Configuration - determines ECM response to inputs used for Dedicated PTO.

* PTO Top Engine Limit - Top RPM Limit for PTO operation.

* PTO Engine RPM Set Speed - provides PTO engine rpm set point for one or two speed control.

* PTO to Set Speed - requires only one circuit to provide one speed control.

* PTO Cab Throttle RPM Limit - provides parameter to limit engine rpm from cab throttle sensor input during PTO operation.

* PTO Vehicle Speed Limit - determines the vehicle speed operating range for PTO.

* Torque Limit - reduces engine torque during PTO operation or when Torque Limit switch is ON.

* PTO Activates Cooling Fan - program for the fan to operate and remain ON during PTO operation.

* Idle/PTO RPM Ramp Rate - determines the rate of engine rpm acceleration/deceleration for PTO operation.

* Idle/PTO Bump RPM - determines the amount of engine rpm change when the Set/Resume switch is toggled.

* Additional Features

* When the PTO On/Off circuit is ON (activated), ECM controlled engine retarder/brakes are disabled.

* When the PTO On/Off circuit is ON (activated), the Idle Shutdown feature is disabled. The PTO Shutdown feature is enabled.

* Prevents the cab clutch and service brake inputs from disengaging an engine set speed for slow moving operations requiring engine rpm control from the cab, such as curb pouring cement trucks.

* PTO Shutdown Time - Reduces driver abuse of disabling idle shutdown by placing the truck in PTO mode.

Figure 1 - PTO Configuration Truck Diagrams

Power Take-Off (PTO) Definition

Power Take-Off (PTO) as referred to in this manual is engine rpm control initiated through a dedicated PTO On/Off circuit connected to the ECM Multi-Function Input #1 (pin-8 of ECM Vehicle Harness Connector J1/P1). Engine rpm control initiated through the Cruise On/Off circuit will be referred to as idle.

Four Programmable PTO Configurations

* Off - Dedicated PTO parameter functions are not available.

* Cab Switches - uses cruise control Set/Resume switch with separate PTO On/Off switch to control engine rpm.

* Remote Switches - uses remote Set/Resume switch with PTO On/Off switch to control engine rpm.

* Remote Throttle - uses remote throttle position sensor with PTO On/Off switch to control engine rpm.

One Speed Control with One Circuit

* Provides an optional PTO Set Speed for those applications where only one speed above low idle is required.

* Required components are a PTO On/Off Switch, PTO Interlock Switch(es) and PTO Switch On Lamp(s).

Two Speed Control with Three Circuits

* Two speed control of engine rpm with PTO preset Set Speed and PTO Top Engine Limit above low idle.

* Required components are a PTO On/Off Switch, PTO Interlock Switch(es), a PTO Set/Resume Switch and PTO Switch On Lamp(s).

Variable Speed Control using Remote Switches

* Required components are a PTO On/Off Switch, PTO Interlock Switch(es), a PTO Set/Resume Switch and PTO Switch On Lamp(s).

Variable Speed Control using a Remote, Second Throttle Sensor Input

* Required components are a PTO On/Off Switch, PTO Interlock Switch(es), PTO Switch On Lamp(s), and Hand Throttle Assembly or Accelerator Pedal Assembly with a Caterpillar Throttle Position Sensor. Pressure governor controls for fire pump applications are also available.

PTO Switch On Lamp

* Provides a PTO Switch On Lamp Output which indicates to the driver/PTO operator that the engine is now in PTO mode.

* Required component is a PTO Switch On Lamp.

* In most applications, indicates PTO Shutdown Time is in Driver Alert Mode. The Check Engine Lamp and the PTO Switch On Lamp flash rapidly to indicate engine shutdown is approaching during last 90 seconds.

Engine RPM Control Using Switches versus Control Using a Throttle Position Sensor

Use switches to control engine rpm if the engine will be operating at specific engine rpm points (i.e. low idle, 1200 rpm, and 1600 rpm). Switches are also recommended if the driver/PTO operator will be frequently varying engine rpm and if the driver/PTO operator will not have a hand or foot free to operate the throttle control/accelerator pedal.

Installing Switches and Components

Before attempting to install the switches and program the parameters for the vehicle application, ensure everyone (owner, operator and installer) understands how the engine and components will be used during the PTO operation. Refer to "Programmable Parameters" on page 14. The questionnaire on the following page will help the installer and the truck owner/driver/PTO operator understand the options available and determine what to install.

Questions 1 thru 7 should be asked before starting the installation procedure. The remaining questions may be asked after the installation is completed to fine tune the programming and other system components. Refer to programmed parameters information described on the "Driver/PTO Operator Programmed Parameter Information Sheet" on page 11. Refer to the Operation & Maintenance Manual for your truck engine or LEKQ3166, Specing Caterpillar Electronic Truck Engines, for additional information.

Recommended Information for Driver/PTO Operators

After the Installation is Completed

When the installation is complete, please complete the "1.0 Installation Questionnaire" on page 8, "Driver/PTO Operator Programmed Parameter Information Sheet" on page 11, "Driver/PTO Operator Instructions" on page 12, "Truck Installation Diagram - Switches and Components" on page 13 and "Programmable Parameters" on page 14.

Explain the installation to the truck owner/driver/PTO operator, and leave the questionnaire, information sheet, etc, in the vehicle glove box. This will allow the driver/PTO operator(s) to review the truck set up, and also help the mechanic/service technician understand how to troubleshoot any suspected problems relating to the installation in the future.

1.0 Installation Questionnaire

Installation and Programming Based on Questionnaire Response.

Driver/PTO Operator Programmed Parameter Information Sheet

Driver/PTO Operator Instructions

Truck Installation Diagram - Switches and Components

1. Diagram the switches, sensors, and lamps used, and their locations. Refer to the "Figure 1 - PTO Configuration Truck Diagrams" on page 6, and the particular PTO Configuration Truck Diagrams in this manual for examples.

2. Provide a copy of the appropriate wiring diagrams, worksheets, etc, from this manual which illustrates the specific installation.

Figure 2 - Installed Location of Switches and Components

Programmable Parameters

Understanding Programmable Engine Limits

There are three programmable engine limits available with the C-10, C-12 & 3406E electronic system.

The first is the Top Engine Limit. The Top Engine Limit has a programmable range from 1600 rpm to 2120 rpm (in one rpm increments). This limit is used while driving the vehicle over the road. It determines the maximum rpm the engine will achieve when the PTO On/Off switch is in the OFF position.

The second programmable engine limit is the Idle RPM Limit. This is the maximum rpm set speed limit if the engine rpm is established using the Cruise Control On/Off switch and the Cruise Control Set/Resume switch. The programmable range is from 600 to 2120 rpm (in one rpm increments). The minimum programmable Idle RPM Limit is affected and determined by the programmed Low Idle RPM. The maximum programmable Idle RPM Limit is limited by the programmed Top Engine Limit.

The third engine limit is the PTO Top Engine Limit. The PTO Top Engine Limit has a programmable range from 600 to 2120 rpm (in one rpm increments). The minimum programmable PTO Top Engine Limit is actually determined by the programmed Low Idle RPM. The maximum programmable PTO Top Engine Limit is 2120 rpm. The PTO Top Engine Limit can be programmed above the programmed Top Engine Limit, allowing a higher engine rpm when the PTO On/Off switch is in the ON position.

The following Tables (1 thru 10) define a sequence of events. They begin with the Driver/PTO Operator Action using Controlling Equipment positions. These positions affect Engine RPM Results within specific programmed limits.

PTO Engine RPM Set Speed

This parameter is useful only if one or two specific engine rpm above low idle are required when the PTO On/Off switch is in the ON position. Program this parameter to the same value as the PTO Top Engine Limit if ONLY one specific engine rpm above low idle is required.

This parameter determines the engine rpm that the engine will advance to when the PTO On/Off switch is turned to the ON position, and the PTO to Set Speed Parameter is programmed to YES. If PTO to Set Speed is programmed to NO, this speed can be achieved using the RPM Increase/RPM Decrease (Set/Resume) Switch.

NOTE: The PTO Engine RPM Set Speed parameter programming can override the Idle/PTO Bump RPM parameter for PTO. If PTO Engine RPM Set Speed is programmed above 0 rpm, the Set/Resume inputs function as RPM Increase/RPM Decrease instead of Set/Resume when the PTO On/Off switch is ON.

Table 2 illustrates PTO operation with two specific speeds above low idle.

Table 2 also provides an example of the PTO Engine RPM Set Speed parameter for applications requiring engine operation at low idle, an intermediate speed, and the PTO Top Engine Limit.

Table 3 illustrates PTO operation with one specific speed above low idle. Refer to "Table 4: PTO to Set Speed Engine Operation" on page 20 for an example of the PTO to Set Speed parameter.

PTO to Set Speed

Program this parameter to YES to have engine rpm accelerate to the PTO Engine RPM Set Speed when the PTO On/Off circuit is ON. This is useful for those applications requiring only one specific engine rpm above low idle, because only one circuit is required.

Programmable Torque Limit

NOTE: Some Oil Well Service application Personality Modules have two torque curves. Enabling these torque curves require PTO Configuration programmed to Cab Switches, Remote Switches or Remote Throttle. DO NOT program torque limits for this application, it is already programmed in the Personality Module.

Programming this parameter provides an engine torque limit for PTO operation or other special situations. The programmable range of this parameter is 200 to 2000 lb ft in 1 lb ft increments (270 to 2700 N·m in 1 N·m increments). Programming the Torque Limit above the rated torque of the engine will not provide additional torque. The engine will operate using its normal torque curve whenever the normal torque is less than the programmed value of the Torque Limit.

The following two illustrations demonstrate the Torque Limit for PTO use, and when PTO is OFF. Be aware that the programmed Torque Limit will apply whenever PTO On/Off is ON, also when the Torque Limit Switch is ON (which occurs only when the PTO On/Off switch is OFF. Refer to "Figure 22 - Truck Diagram - Cab Switches with Torque Limiting and Disabling Brake/Clutch Kickout of PTO Set Speed" on page 40 and "Figure 24 - Truck Diagram - Remote Switches with Torque Limiting and Disabling Brake/Clutch Kickout of PTO Set Speed Torque Limit" on page 41). Typically, the Torque Limit switch illustrated will be part of the system requiring the torque limit. For example, a switch in the transmission for deep reduction gears is a transmission system requiring the torque limit. Program the Torque Limit to the rated torque of the device it is protecting.

NOTE: The programmed torque level is an estimate. To achieve precise torque limiting, a chassis dynamometer may be required.

PTO Cab Throttle RPM Limit

This parameter applies only when PTO Configuration is programmed to Cab Switches. For PTO Configuration programmed to Remote Switches or Remote Throttle, the cab is always limited to low idle. When the PTO On/Off circuit is ON, the cab Throttle Position Sensor is limited to the value of the PTO Cab Throttle RPM Limit. This is useful for applications with equipment that may be damaged by engine overspeed. This parameter has three programmable choices. They are Low Idle, Top Engine Limit, or PTO Top Engine Limit.

1. If programmed to Low Idle, the engine will not exceed the programmed Low Idle if the accelerator pedal is depressed with the PTO On/Off circuit ON (the accelerator pedal is ignored).

2. If programmed to Top Engine Limit, depressing the accelerator pedal will allow the engine to achieve the programmed Top Engine Limit when the PTO On/Off circuit is ON.

3. If programmed to PTO Top Engine Limit, depressing the accelerator pedal will allow the engine to reach the programmed PTO Top Engine Limit when the PTO On/Off circuit is ON.

Three examples are illustrated in Table 7, Table 8 and Table 9 to describe each of the three options for this parameter; Low Idle, Top Engine Limit, and PTO Top Engine Limit.

Idle/PTO RPM Ramp Rate

This parameter determines the rate of acceleration and deceleration of the engine when the engine rpm is changing because of actuation of the Set/Resume switch, Idle/PTO Bump RPM, PTO to Set Speed, or the PTO Engine RPM Set Speed parameters.

NOTE: This mode or condition does not apply to engine rpm acceleration and deceleration due to a throttle position sensor.

The parameter is programmed in one rpm per second increments from 5 to 1000 rpm per second. This parameter should be programmed to match the application to provide reduced cycle times for those applications where a reduced cycle time is critical.

NOTE: Programming excessive ramp rates may stress PTO driven equipment.

Idle/PTO Bump RPM

Program this parameter to change the engine rpm (increase or decrease) when the Set/Resume switch is toggled for precise engine rpm control from the cab.

NOTE: If the PTO Engine RPM Set Speed is programmed to any value (except zero), the parameter is overridden.

For example, the Idle/PTO Bump RPM would only apply to engine Idle, when the Cruise Control On/Off Switch is in the ON position, the PTO On/Off circuit is OFF, and the Cruise Control Set/Resume Switch is toggled.

PTO Activates Cooling Fan

If the ECM is NOT part of the cooling fan control there is no reason to program this parameter. This parameter requires the cooling fan control system to use the engine Electronic Control Module (ECM) for the cooling fan control. Contact the vehicle manufacturer to determine if the ECM is controlling the fan for your vehicle. If the PTO Activates Cooling Fan parameter is programmed to Continuous, the ECM will turn the cooling fan ON whenever the PTO On/Off switch is ON.

NOTE: In cold weather, continuous fan operation may cause the engine operating temperature to be too low.

If the PTO Activates Cooling Fan parameter is programmed to Normal, the ECM will turn the cooling fan ON only when coolant temperature value, inlet manifold temperature value, etc, signal to the ECM there is a need to begin operating the fan. Usually the load introduced to the engine when the fan begins operation is not significant enough to create problems for the PTO operation.

PTO Vehicle Speed Limit

This parameter applies to setting an engine rpm using the PTO On/Off or Cruise Control On/Off switches. Programmable range is 1 to 127 mph in one mph increments (2 to 204 km/h in one km/h increments). Program this parameter to 1 to disable PTO Set RPM while vehicle is moving. The PTO Mode Vehicle Speed Limit determines the PTO vehicle speed range the engine control will allow. The setting of an engine rpm, and the vehicle speed limit (if exceeded), will cause disengagement of an active set rpm.

NOTE: If the PTO Vehicle Speed Limit parameter is used to avoid vehicle speed circuit disconnection because the PTO is transmission driven, parking brake switch and neutral switch interlocks are required in the PTO On/Off Switch circuit. Refer to Figure 26 on page 42.

Cruise/Idle/PTO Switch Configuration

This parameter will determine the Accel and Decel function of both the Cruise Control On/Off and PTO On/Off controlled Set/Resume switch when the switch is toggled to bump up the rpm or, held in position for a constant acceleration. The Caterpillar factory default is Set-Accel/Resume-Decel. This can be changed to Set-Decel/Resume-Accel using Caterpillar Electronic Service Tools.

NOTE: When PTO On/Off Switch is in the ON position, and the PTO Engine RPM Set Speed is programmed to one rpm or above, the Set Switch serves as RPM Increase and the Resume Switch serves as RPM Decrease regardless of the programmed Cruise/Idle/PTO Switch Configuration.

PTO Shutdown Time

This parameter provides engine shutdown ability similar to Idle Shutdown and reduces driver abuse of disabling idle shutdown by using PTO mode. If PTO Shutdown Time is programmed, the timer will become active when PTO is switched ON and can not be overridden. When the elapsed time is within 90 seconds of the programmed value the PTO Shutdown Time enters Driver Alert Mode. The Check Engine Lamp and the PTO Switch On Lamp flash rapidly to indicate engine shutdown is approaching. When the elapsed time equals the programmed value the engine will shutdown regardless of load.

NOTE: When Transmission Style parameter is programmed to Eaton Top 2 Multi-Function Output #1 is not available for connection to the PTO Switch On Lamp circuit and the PTO Switch On Lamp will not flash when the PTO Shutdown Time is in Driver Alert Mode.

Engine Monitoring

Caterpillar C-10, C-12 & 3406E engines have an engine monitoring feature available. The engine will respond to a high coolant temperature value, a low oil pressure value, or a low coolant level depending on how this parameter is programmed. The parameter can be programmed to Off, Warning, Derate, or Shutdown. Refer to the engine Operation & Maintenance Manual for additional information regarding this feature.

Programming the Parameters

Programming the parameters requires an Electronic Service Tool, and if programmed, Customer Passwords. Availability of some of the parameters depends upon the programming of other parameters. Before attempting to program any of the Dedicated PTO Parameters, program the PTO Configuration Parameter first. Failure to program the PTO Configuration Parameter first will cause the remaining Dedicated PTO Parameters to indicate Not Installed on the Electronic Service Tool Status Screen.

Programming Provisions

The following parameters or their operation are affected by other parameter settings as indicated.

* PTO Configuration- All "Dedicated PTO Parameters" require the PTO Configuration Parameter to be programmed first (from PTO On/Off circuit OFF position) before any other parameter can be programmed to enable/allow programming other "Dedicated PTO Parameters".

* PTO Top Engine Limit- this parameter should be programmed above the programmed Low Idle.

* PTO Engine RPM Set Speed- programming this parameter overrides/disables the Idle/PTO Bump RPM for PTO operation.

* PTO to Set Speed- requires PTO Engine RPM Set Speed programmed to an engine rpm above Low Idle.

* PTO Cab Throttle RPM Limit- applies only if the PTO Configuration is programmed to Cab Switches. If the PTO Configuration is programmed to Remote Switches or Remote Throttle, the cab Throttle Position Sensor is always limited to Low Idle when the PTO On/Off circuit is ON.

* PTO Activates the Cooling Fan- requires the Caterpillar ECM connection to, and part of, the cooling fan control.

* Torque Limit- the Torque Limit can be programmed to values above the Rated Torque of the engine, but doing so is meaningless. The Rated Torque of the engine is the maximum torque of the engine.

* Cruise/Idle/PTO Switch Configuration- if the PTO Engine RPM Set Speed parameter is programmed, the Set/Resume switch operates as an RPM Increase/RPM Decrease switch when the PTO On/Off switch is ON. Placing the switch in the Set position will indicate to the ECM a desire to increase engine rpm. Placing the switch in the Resume position will indicate to the ECM a desire to decrease engine rpm.

* PTO Vehicle Speed- If the PTO Vehicle Speed Limit parameter is used to avoid vehicle speed circuit disconnection because the PTO is transmission driven, parking brake switch and neutral switch interlocks are required in the PTO On/Off Switch circuit.

* PTO Shutdown Time- If PTO Shutdown Time is programmed, the timer will become active when PTO is switched ON and can not be overridden. When the elapsed time equals the programmed value the engine will shutdown regardless of load.

Component Installation

Figure 3 - Electronic Control Module

Installation Considerations

Show/hide table

Preventing unwanted operation of the engine requires careful installation of interlock switches in the system. These interlocks must prevent operation of the engine rpm PTO until the PTO operator is expecting it and is prepared.

A parking brake, transmission neutral switch, PTO operator safety switch, or a combination of these, in addition to the PTO On/Off Switch, should be considered.

* PTO Switch On Lamp

The PTO Switch On Lamp should be installed in the cab and at the PTO operating station (if outside of the cab). This lamp will provide indication to the driver/PTO operator when the PTO On/Off circuit is ON.

* PTO Configuration Programmed to Remote Switches or Remote Throttle

It is important to remember that the cab Throttle Position Sensor, Clutch Switch, Service Brake Switch, and Cruise Control Switches are all ignored when the PTO On/Off circuit is ON if the PTO Configuration is programmed to Remote Switches or Remote Throttle. A PTO Switch On Lamp is recommended in both the cab and at the remote operator station to indicate when the PTO On/Off circuit is ON.

A Parking Brake Switch and/or Transmission Neutral Switch will cause the engine to return to low idle rpm if someone tries to move the vehicle while the PTO operator is at the remote PTO location.

The PTO Vehicle Speed Limit should also be programmed to the minimum, 1 mph (1 km/h), to cause the engine to disengage PTO Set Speeds if the vehicle is moved.

* Engine Shutdown Switch

If an Engine Shutdown Switch is desired, this switch should be connected to a Normally Closed Relay as shown in the Engine Shutdown Switch Wiring Diagram below. The actual location of the switch should be readily accessible to the PTO operator and easily contacted during PTO operation.

Figure 4 - Engine Shutdown Switch Wiring Diagram

Component Electrical Specifications

* Lamp Electrical Requirements

The ECM provides a path to ground which switches the lamp(s) ON. The lamps must be capable of operating with 0.3 Amps or less at 12 VDC. If a relay is used to drive the lamps, it must be able to operate with the same 0.3 Amps or less at 12 VDC. Lamp installations located outside the cab should be environmentally protected.

* Switch Electrical Specifications

The switch contact plating should not corrode or oxidize. Gold plated contacts are recommended. All switches should be environmentally sealed and protected as required by the application.

The applied voltage to switches will normally not exceed 11.5 VDC. Normal current draw through the switches will not exceed 0.005 A (5.0 mA).

Contact "chatter" and momentary opening or closing should not exceed 0.1 seconds (100 milliseconds) in duration. The switches should not open or close due to vibration or shock normally found in the application. Closure of an installed switch must short circuit the input to the PTO Sensor Common (ECM Vehicle Connector P1, pin-30).

* Voltage thresholds measured at the ECM

- Voltage-In-Low less than 0.9 VDC - When switch contacts close (switch closure), ground potential difference, switch voltage drop, and wiring harness voltage drop results must be less than 0.9 VDC between the respective control input and PTO Sensor Common (ECM Vehicle Connector P1, pin-30).

- Voltage-In-High greater than 3.5 VDC - When switch contacts open, pin-to-pin leakage paths in connectors, harnesses, and switches must NOT result in an effective resistance of less than 5,000 Ohms from the respective control input and PTO Sensor Common (ECM Vehicle Connector P1, pin-30).

NOTE: OEM installed switches used as inputs to the ECM must not be connected to the vehicle or cab ground. OEM installed switches must be grounded to the ECM PTO Sensor Common using a dedicated return line to ECM Vehicle Harness Connector J1/P1 pin-30 (Multi-Function Sensor Common/PTO Sensor Common).

Selecting Switch Type

The type of switch required depends upon the type of application required. The Set/Resume or RPM Increase/RPM Decrease Switch is typically a three position momentary switch with a spring return to the OFF (center) position.

The PTO On/Off Switch can be an On/Off, two position switch, either manually, air or hydraulically actuated.

The PTO Interlock Switches are typically air actuated, normally closed switches connected into the Parking Brake air pipe and/or hoses, or the Transmission air pipe and/or hoses. These or all switches may be hydraulically controlled switches or limit switches. All switches located outside the cab should be environmentally sealed and protected.

* Switches

A 112-4073 Switch Assembly is available. The switch is a single pole, single throw, air actuated type.

Figure 5 - 112-4073 Switch Schematic

Throttle Position Sensor Electrical Specifications

Figure 6 - 110-8190 Control - Throttle Position Sensor (12V)

Caterpillar requires the 110-8190 Control - Throttle Position Sensor which is supplied with an 8T8731 Plug Connector (Deutsch HD16-3-96S). The connecting harness will require an 8T8732 Receptacle Connector (Deutsch HD14-3-96P).

NOTE: Do not connect a 110-8190 Control - Throttle Position Sensor to the ECM 8 VDC supply. It must be connected/powered by 12 VDC battery.

NOTE: Pressure Governor Controls are available for Fire Pump applications using Remote Throttle PTO Configuration. Refer to "Figure 21 - Wiring Diagram - Fire Pump Pressure Governor Control Using Remote Throttle PTO Configuration" on page 39.

Mounting the Throttle Position Sensor

The 110-8190 Control - Throttle Position Sensor can be attached to either an accelerator pedal assembly (contact the vehicle OEM for parts) or a 107-2281 Mounting Block Assembly (or Williams part number 131446). The 107-2281 Mounting Block Assembly does not include handle and may be used in applications where a mechanical linkage is required.

Figure 7 - Accelerator Pedal/Throttle Assembly Options

Harness Specifications

The installed harness should be protected from the environment using corrugated plastic conduit or other means. All wire should be 18 AWG or larger, SAE J1128 Type SXL or equivalent. The acceptable range for wire insulation outside diameter is 2.54 to 3.43 mm (0.10 to 0.135 inches) for the Deutsch 40-Pin ECM Customer Connector. All ring terminals and splices connected to the harness routing to the engine ECM must be sealed using Raychem ES2000 shrink tube or equivalent.

Figure 8 - Deutsch Components

PTO Switch On Lamp

PTO Switch On Lamps are recommended to provide indication when the PTO On/Off circuit is ON (ECM Vehicle Harness Connector J1/P1, pin-8 is connected to ECM Vehicle Harness Connector J1/P1, pin-30) and for Driver Alert of PTO Shutdown (the Check Engine Lamp is also utilized for Driver Alert).

If the installation requires engine rpm control from outside of the cab (PTO Configuration programmed to Remote Switches or Remote Throttle), lamps installed in both the cab, and at the remote PTO operator location is recommended. The lamps should be placed in a highly visible area for the driver/PTO operator.

If an Eaton Top 2 Transmission is installed and the Transmission Style parameter is programmed to Eaton Top 2, the PTO Switch On Lamp circuit is not connected to the ECM. Refer to "Figure 12 - PTO Switch On Lamp Circuit With Eaton Top 2 Transmissions" on page 33. In this application it should be noted the PTO Switch On Lamp will not flash when the PTO Shutdown Time is in Driver Alert Mode.

Lamp Operation

Installation for the PTO Configurations

PTO Configuration

The diagrams on the following pages illustrate the possible location of each of the components as well as wiring diagrams for various PTO Configurations.

Cab Switches

Figure 13 - Truck Diagram - Cab Switches

Figure 14 - Wiring Diagram - Cab Switches

PTO Configuration Cab Switches - This Configuration provides the advantage of not requiring splices into the existing cab wiring. The Cruise Control Set/Resume Switch is used for PTO Operation, Cruise Control and Idle. The function of the Set position and Resume position is determined by the programming of the PTO Engine RPM Set Speed, Cruise/Idle/PTO Switch Configuration, and Idle/PTO Bump RPM parameters.

If the PTO Engine RPM Set Speed is programmed above 0 rpm, the Set position becomes RPM Increase, the Resume position becomes RPM Decrease. If the PTO Engine RPM Set Speed is programmed to 0 rpm, the Set position provides either the Accel or Decel function and the Resume position provides either Decel or Accel with a programmable bump rpm determined by the Idle/PTO Bump RPM parameter.

Remote Switches

Figure 15 - Truck Diagram - Remote Switches

Figure 16 - Wiring Diagram - Remote Switches

PTO Configuration Remote Switches - The PTO Set/Resume Switch is used for PTO Operation in Figure 15 and Figure 16. The function of the Set position and Resume position is determined by the programming of the PTO Engine RPM Set Speed, Cruise/Idle/PTO Switch Configuration, and Idle/PTO Bump RPM parameters.

If the PTO Engine RPM Set Speed is programmed above 0 rpm, the Set position becomes RPM Increase and Resume becomes RPM Decrease.

If the PTO Engine RPM Set Speed is programmed to 0 rpm, the Set position provides either the Accel or Decel function and Resume either Decel or Accel with a programmable bump rpm determined by the Idle/PTO Bump RPM parameter.

Remote Switches with One Speed Above Low Idle

Figure 17 - Truck Diagram - Remote Switches with One Speed Above Low Idle

Figure 18 - Wiring Diagram - Remote Switches

For the PTO Configuration Remote Switches with one programmed speed above low idle, the PTO Set/Resume Switch is NOT used for PTO Operation. For the circuit in Figure 17 and Figure 18, PTO On to Set Speed should be programmed to YES, and the PTO Engine RPM Set Speed must be programmed to the desired rpm.

Remote Throttle

Figure 19 - Truck Diagram - Remote Throttle

Figure 20 - Wiring Diagram - Remote Throttle

PTO Configuration Remote Throttle - The PTO Set/Resume Switch is NOT available for PTO Operation. For the circuit in Figure 19 and Figure 20, the ECM monitors the Remote Throttle Position Sensor when the PTO On/Off and PTO Interlock Switches are closed.

Remote Throttle - Fire Pump Pressure Governor Control

Figure 21 - Wiring Diagram - Fire Pump Pressure Governor Control Using Remote Throttle PTO Configuration

NOTE: For more information contact the following fire pump pressure governor controller manufacturers.

Cab Switches with Torque Limiting and Disabling Brake/Clutch Kickout

Figure 22 - Truck Diagram - Cab Switches with Torque Limiting and Disabling Brake/Clutch Kickout of PTO Set Speed

Figure 23 - Wiring Diagram - Cab Switches with Torque Limiting and Disabling Brake/Clutch Kickout of PTO Set Speed

Remote Switches with Torque Limiting and Disabling Brake/Clutch Kickout

Figure 24 - Truck Diagram - Remote Switches with Torque Limiting and Disabling Brake/Clutch Kickout of PTO Set Speed Torque Limit

Figure 25 - Wiring Diagram - Remote Switches with Torque Limiting and Disabling Brake/Clutch Kickout of PTO Set Speed Torque Limit

PTO Interlocks - Transmission Driven PTO (Any PTO Configuration)

Figure 26 - Wiring Diagram - Recommended PTO Switch On Circuit For Transmission Driven PTO

PTO Interlocks - If the PTO Vehicle Speed Limit parameter is used to avoid vehicle speed circuit disconnection because the PTO is transmission driven, parking brake switch and neutral switch interlocks are required in the PTO On/Off Switch circuit.

Torque Limit

* Cab Switches

The PTO Configuration Cab Switches are used in Figure 22 and Figure 23 on page 40. The diagrams also include the ability to use a programmed Torque Limit when the PTO On/Off switch is in either the ON or OFF position. Torque Limit always applies when the PTO On/Off switch is in the ON position. The diagrams illustrate how to connect a second switch to provide the Torque Limit under other conditions when driving over the road and the PTO On/Off switch is in the OFF position. This is useful, for example, if the transmission provides deep reduction gears requiring reduced torque levels for the driveline.

* Remote Switches

The PTO Configuration Remote Switches are used in Figure 24 and Figure 25 on page 41. The diagrams also include the ability to use a programmed Torque Limit when the PTO On/Off switch is in the ON or OFF position. If a Torque Limit is programmed, it always applies when the PTO On/Off switch is in the ON position. The diagrams illustrate how to connect a second switch to provide the Torque Limit under other conditions when driving over the road and the PTO On/Off switch is in the OFF position. This is useful, for example, if the transmission provides deep reduction gears requiring reduced torque levels for the driveline.

Interlock Sw#1 and Interlock Sw#2 should actuate/switch at the same time into the positions shown in the diagrams. If the PTO On/Off Switch is OFF, the ECM considers connection of ECM Vehicle Harness Connector J1/P1 pin-32 to J1/P1 pin-30 (Torque Limit Switch closed and Interlock Sw #1 in lower position) as a request to limit torque to the programmed Torque Limit.

Brake/Clutch Disable Switch

* Cab Switches

The Brake/Clutch Disable Switch is intended for applications requiring mobile use of the vehicle with an engine rpm set, and NOT requiring the Brake or Clutch to disengage or disable the engine rpm set speed. This is useful for firetruck, asphalt or cement pavement or curb pouring operations.

* Remote Switches

The Brake/Clutch Disable Switch is intended for applications requiring mobile use of the vehicle with an Idle engine rpm set (an rpm set using the Cruise Control On/Off and Cruise Control Set/Resume switches), and NOT requiring the Brake or Clutch to disengage or disable the engine rpm set speed. This is useful for firetruck, asphalt or cement pavement or curb pouring operations.

Interlock Sw#1 and Interlock Sw#2 should actuate/switch at the same time into the positions shown in the diagrams. If the PTO On/Off Switch is OFF, the ECM considers connection of ECM Vehicle Harness Connector J1/P1 pin-31 to J1/P1 pin-30 (Brake/Clutch Disable Switch closed and Interlock Sw #2 in lower position) as a request to prevent the disengagement of an Idle set speed.

This feature applies only when the vehicle speed is below the programmable PTO Vehicle Speed Limit and an engine rpm is set.

For the PTO Configuration Remote Switches the PTO Set/Resume Switch is used for PTO Operation in Figure 25 on page 41. The function of the Set position and Resume position is determined by the programming of the PTO Engine RPM Set Speed, Cruise/Idle/PTO Switch Configuration, and Idle/PTO Bump RPM parameters.

If the PTO Engine RPM Set Speed is programmed above 0 rpm, the Set position becomes RPM Increase and Resume position becomes RPM Decrease. If the PTO Engine RPM Set Speed is programmed to 0 rpm, the Set position provides either the Accel or Decel function RPM Increase and Resume position either Decel or Accel with a programmable bump rpm determined by the Idle/PTO Bump RPM parameter.

Idle Shutdown Disabled with PTO Switch On

Whenever the PTO On/Off Switch circuit is ON, the ECM disables the Idle Shutdown Timer to prevent unwanted shutdowns while in PTO mode. If there is concern about the driver abusing the disabled Idle Shutdown, the PTO On/Off Switch or Interlocks should be arranged to make this more difficult. If possible, incorporate the PTO On/Off Switch into the PTO activation system. A PTO Shutdown Timer programmable parameter is also provided. This timer will shut down the engine when the ECM is programmed to use Dedicated PTO Parameters, PTO Shutdown Time parameter is programmed, and ECM Multi-Function Input #1 is ON (ECM is in PTO mode).

NOTE: Fuel rates are not monitored while PTO Shutdown Timer is active and shutdown will occur regardless of load. The PTO Shutdown Timer cannot be overridden using the service brake or clutch like the Idle Timer can.

NOTE: It is critical that the PTO operator using the vehicle know and understand how the PTO system is set up and operates.

Troubleshooting the PTO Installation

This procedure is intended to confirm the PTO switches, PTO Throttle Position Sensor and PTO Switch On Lamp circuits in the vehicle are installed and operating correctly.

Diagnostic Codes

Functional Test