On-Highway Engines Electronic PTO Installation and Application Guide Caterpillar

Illustration 1	g01114384
Typical view of the left side of an electronic engine (1) Vehicle harness connector J1/P1 (2) Engine harness connector J2/P2 (3) Engine Control Module (ECM) (4) ECM side of vehicle harness connector P1 (5) Side view of vehicle harness connector P1 (6) Harness side of vehicle harness connector P1

Considerations for the Installation

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The switches labeled "PTO Interlock" in the schematics are redundant and should be added to ensure the engine is put in PTO mode only when the vehicle and operator are prepared for safe PTO operation. The interlocks must prevent operation of the engine PTO until the PTO operator is expecting it and is prepared. These switch(es) may be (parking brake switch or other switches) available as an interlock and are required for the application.

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NOTICE
It is the installer and the vehicle owner's responsibility to determine the necessary interlocks for the PTO system and to provide the PTO operator with the operating instructions. Failure to do so may cause vehicle/equipment damage.

PTO Switch On Lamp

Note: If the"Engine Monitoring lamps" parameter is programmed to "Option 1" and the parameter for the coolant level sensor is programmed to "No", then J1/P1-30 can be used to connect a PTO switch on lamp.

Note: "Option 1" is not available for the GM Truck Manufacturer.

The PTO switch on lamp should be installed in the cab. If the PTO operating station is outside of the cab, a lamp should also be installed at the operating station. This lamp will provide an indication to the driver/PTO operator when the PTO On/Off circuit is ON. Refer to the appropriate diagrams for the application. If the PTO Configuration is programmed to "Cab Switches", then refer to Illustrations 7 and 8. If the PTO Configuration is programmed to "Remote Switches", then refer to Illustrations 9 and 10. If the PTO Configuration is programmed to "Remote Throttle", then refer to Illustrations 11 and 12.

The PTO Configuration is Programmed to "Remote Switches" or to "Remote Throttle"

The components that follow are ignored when the PTO On/Off circuit is in the ON position. The configuration of the PTO must also be programmed to "Remote Switches" or to "Remote Throttle": accelerator pedal position sensor for the cab, clutch switch, service brake switch and cruise control switches. A PTO Switch On lamp is recommended in both the cab and at the remote station in order to indicate when the PTO On/Off circuit is ON. The parking brake switch and/or a transmission neutral switch causes the engine to return to the low idle rpm. The engine will return to the low idle rpm if someone tries to move the vehicle and the operator of the PTO is at the remote location. The "Idle/PTO Vehicle Speed Limit" should also be programmed to the minimum 1 km/h (1 mph) in order to cause the engine to return to low idle if the vehicle is moved.

PTO Engine Shutdown Switch

Note: The PTO Engine Shutdown Switch is for Medium-Duty Engines. 3126B, 3126E, C7, and C9.

Illustration 2	g01027013
Circuit schematic for the PTO Engine Shutdown Switch

An input is available to the ECM for connecting a switch to shut down the engine while the engine is operating in PTO mode. To use this feature, the parameter "PTO Configuration" must be programmed to "Cab Switches", "Remote Switches", or "Remote Throttle". The following conditions must also be met in order to use this feature.

• "PTO Engine Shutdown Switch" must be programmed to "P1/J1-7" or "P1/J1-23".

• The PTO On/Off switch is in the ON position and the PTO is active.

• The PTO Engine Shutdown Switch is in the ON position.

• 186-04 PTO Engine Shutdown Switch voltage low is not active.

• The vehicle speed is equal to zero.

• No vehicle speed faults are active.

If the vehicle speed is not equal to zero, or if there are active vehicle speed faults, the engine will go to low idle. The engine will not shut down when the vehicle speed falls to zero. When the PTO Engine Shutdown Switch is pressed, a 186-14 PTO Engine Shutdown Switch Occurance will become active. The code will stay active until the engine shuts down. When the engine shuts down, the code will be logged.

Engine Shutdown Switch

If an engine shutdown switch is desired, then the switch should be connected to a Normally Closed Relay. Refer to Schematics 3 for an example. The actual location of the switch should be readily accessible to the operator of the PTO during PTO operation.

Schematics for the Engine Shutdown Switch

Illustration 3	g01042385
Schematic for the engine shutdown switch for a full feature system

PTO Interlocks for Transmission Driven PTO

Any PTO Configuration

Vehicles that use a transmission driven PTO may require an additional Parking Brake Interlock Switch for the PTO On/Off circuit. The interlock will prevent PTO operation if the Parking Brake is not set.

Illustration 4	g01026473
Schematic for the PTO interlock for transmission driven PTO

Installation of Fast Idle Configuration

Fast Idle Configuration

Note: The Fast Idle option is not available on all engines.

Note: The Fast Idle Lamp output may not be available. This is determined by the engine programming.

Illustrations 5 and 6 show the location of the components as well as the wiring diagram for the fast idle. Fast idle operation is not an integral part of PTO operation. Fast idle operation provides another method that controls the engine speed that is similar to PTO operation.

Illustration 5	g01298737
Fast idle configuration (A) Fast idle switch (B) Fast idle enabled lamp (C) ECM side of the vehicle harness connector P1 (D) Harness side of the vehicle harness connector P1 (P1-6) AP sensor/switch sensor common (P1-31) Output 9 (fast idle enabled lamp) (P1-40) Input 18 (fast idle enable switch)

Illustration 6	g01026544
Fast idle schematic

Installation for Three PTO Configurations

The PTO configuration provides three programmable options:

• "Cab switches"

• "Remote switches"

• "Remote throttle"

The information in this section provides details on the installation of the necessary components that are required for the various options for the PTO configuration.

PTO Configuration for Cab Switches

No splicing into the existing cab wiring is necessary. The Cruise Control Set/Resume Switch is used for PTO Operation, Cruise Control, and Extended Idle. The function of the Set position and Resume position is determined by the programming of the following parameters: "PTO Engine RPM Set Speed", "Cruise/Idle/PTO Switch Configuration" and "Idle/PTO Bump RPM"

The Set position becomes the RPM increase position and the Resume position becomes the RPM decrease position if the PTO Engine RPM Set Speed is programmed above 0 rpm. If the PTO Engine RPM Set Speed is programmed to 0 rpm, then the Set position can provide either the ACCEL or the DECEL function and the Resume position can provide either the DECEL function or the ACCEL function. A programmable bump rpm is determined by the "Idle/PTO Bump RPM" parameter.

Note: A Neutral Switch (Input 12, J1/P1 terminal-62) is required for PTO operation if the PTO Configuration is programmed to "Cab Switches" and the "Transmission Style" is programmed to one of the following options: "Universal (GM ONLY)", "Automatic Option 3", "Automatic Option 4", "AT/MT/HT Option 3" and "AT/MT/HT Option 4".

Illustration 7	g01298959
Configuration of the cab switches (A) Set/Resume switch (B) PTO On/Off switch (C) PTO Switch On lamp (D) ECM side of the vehicle harness connector P1 (E) Harness side of the vehicle harness connector P1 (P1-3) Input sensor common 2 (P1-30) Output 1 (PTO switch On lamp) (P1-56) Input 1 (PTO On/Off switch)

Illustration 8	g01026566
Schematic for cab switches

PTO Configuration for Remote Switches

The Cruise Control Set/Resume switch that is in the cab is not used. "Remote switches PTO configuration" requires the installation of a remote set switch and the installation of a remote resume switch. While the PTO is in operation, all of the cab controls will be ignored.

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 the "Idle/PTO Bump RPM" parameters.

The Set position becomes the RPM increase position and the Resume position becomes the RPM decrease position if the "PTO Engine RPM Set Speed" is programmed above 0 rpm. If the "PTO Engine RPM Set Speed" is programmed to 0 rpm, then the Set position can provide either the ACCEL or the DECEL function and the Resume position can provide either the DECEL function or the ACCEL function. A programmable bump rpm is determined by the "Idle/PTO Bump RPM" parameter.

Illustration 9	g01298965
Configuration of the remote switches (A) PTO On/Off Switch (B) The PTO Set/Resume switch may be located in the cab or in a remote location. The operation of the PTO Set/Resume switch is dependent upon the programming. (C) PTO Switch On lamp (D) PTO Switch On lamp (E) ECM side of the vehicle harness connector J1 (F) Harness side of the vehicle harness connector P1 (P1-3) "Input sensor common 2" (P1-30) "Output 1" (PTO switch On lamp) (P1-56) "Input 1" (PTO On/Off switch) (P1-58) "Input 2" (PTO set switch) (P1-60) "Input 3" (PTO resume switch)

Illustration 10	g01026634
Schematic for remote switches

PTO Configuration for Remote Throttle

The ECM monitors the remote accelerator position sensor when the PTO On/Off switch and the PTO Interlock switches are closed. The PTO set switch can be used to set engine rpm and the PTO resume switch is available to resume a previously set rpm. The switch will go to the ACCEL position or the switch will go to the DECEL position from the current set speed if the PTO set switch is held in position or the PTO resume switch is held in position. This is based on the programming for the customer specified parameter.

Illustration 11	g01298995
Configuration for remote throttle (A) PTO Switch On lamp (B) PTO On/Off switch (C) The PTO Set/Resume switch may be located in the cab or in a remote location. The operation of the PTO Set/Resume switch is dependent upon the programming. (D) PTO Switch On lamp (E) PTO Accelerator Assembly (F) ECM side of vehicle harness connector P1 (G) Harness side of the vehicle harness connector P1 (P1-3) Input sensor common 2 (P1-30) Output 1 (remote PTO switch On lamp) (56) Input 1 (PTO On/Off switch) (P1-58) Input 2 (PTO Set switch) (P1-60) Input 3 (PTO Resume switch) (P1-68) Input 8 (remote accelerator)

Illustration 12	g01026653
Schematic for remote throttle

Cab Switches with Torque Limiting and Ignore Brake/Clutch Switch

Cab Switches with Torque Limiting

The "Cab Switches PTO" configuration is used in Illustrations 13 and 14. The illustrations also include the ability to use a programmed Torque Limit when the PTO On/Off switch is in either the ON or the OFF position (MARCH 1998 or later Personality Modules). The Torque Limit is used when the Torque Limit has a programmed value and the PTO On/Off switch is in the ON position. The illustrations show the connection of a second switch in order to provide the Torque Limit under certain conditions. The Torque Limit is operational when driving the vehicle and the PTO On/Off switch is in the OFF position. For example, this is useful when the transmission provides deep reduction gears that require reduced torque levels for the driveline. This feature should only be used for temporary protection of the equipment. To enable this feature, Input 4 must be programmed to "Torque Limit Switch". The default is "None".

Cab Switches with Ignore Brake/Clutch Switch

The Ignore Brake/Clutch switch is intended for applications that require mobile use of the vehicle with a set engine rpm. The PTO will disengage if the brake is depressed or if the clutch is depressed. The Ignore Brake/Clutch switch prevents the clutch or the brake from disengaging the PTO set speed. This is useful for the following applications: fire truck, cement pavement and curb pouring operations. In order to enable this feature, Input 5 must be programmed to "Ignore Brake/Clutch Switch". The default is "None".

Illustration 13	g01299003
Configuration for cab switches with torque limiting and ignore brake/clutch switch (A) Set/Resume switch (B) PTO On/Off switch (C) PTO switch on lamp (D) Torque limit switch (E) Ignore/Normal Brake/Clutch switch (F) ECM side of the vehicle harness connector P1 (G) Harness side of the vehicle harness connector P1 (P1-3) Input sensor common 2 (P1-7) Input 4 (torque limit switch) (P1-30) Output 1 (PTO switch On lamp) (P1-47) Input 5 (Brake/Clutch disable switch) (P1-56) Input 1 (PTO On/Off switch)

Illustration 14	g01026669
Schematic for cab switches with torque limiting and ignore brake/clutch switch

Remote Switches with Torque Limiting and Ignore Brake/Clutch Switch

Remote Switches with Torque Limiting

The "Remote Switches PTO" configuration is used in Illustration 15 and in Illustration 16. The illustrations also show the ability to use a programmed "Torque Limit" when the PTO On/Off switch is in the "ON" or "OFF" position (MARCH 1998 or later Personality Modules). The Torque Limit is used when the Torque Limit has a programmed value and the PTO On/Off switch is in the ON position. The diagrams illustrate the connection of a second switch in order to provide the Torque Limit under certain conditions. The Torque Limit is operational when driving and the PTO On/Off switch is in the OFF position. For example, this is useful when the transmission provides deep reduction gears that require reduced torque levels for the driveline. This feature should only be used for temporary protection of the equipment. To enable this feature, Input 4 must be programmed to "Torque Limit Switch". The default is "None".

Remote Switches with Ignore Brake/Clutch Switch

The Ignore Brake/Clutch switch is not required for the "remote switches PTO configuration". If the "remote switches PTO configuration" is used in conjunction with extended idle or fast idle, an Ignore Brake/Clutch switch can be installed. The Ignore Brake/Clutch switch will prevent the clutch or the brake from disengaging an extended idle speed or fast idle speed.

Note: If the "Transmission Style" is programmed to "Automatic Option 3" or to "Automatic Option 4", then provisions must be taken in order to prevent the neutral switch from disengaging the PTO when the transmission is in gear.

Illustration 15	g01299017
Configuration for remote switches with torque limiting and ignore brake/clutch switch (A) PTO switch on lamp (B) PTO On/Off switch (cab or remote location) (C) PTO Set/Resume switch (D) PTO switch on lamp (E) Torque limit switch (F) Ignore/Normal Brake/Clutch switch (G) ECM side of the vehicle harness connector P1 (H) Harness side of the vehicle harness connector P1 (P1-3) Input sensor common 2 (P1-7) Input 4 (torque limit switch) (P1-30) Output 1 (Remote PTO Switch On lamp) (P1-47) Input 5 (Brake/Clutch disable switch) (P1-56) Input 1 (PTO On/Off switch) (P1-58) Input 2 (PTO Set switch) (P1-60) Input 3 (PTO Resume switch)

Illustration 16	g01026696
Schematic for remote switches with torque limiting and ignore brake/clutch switch

Idle Shutdown is Disabled with the PTO Switch ON

The ECM will disable the "Idle Shutdown Timer" when the circuit for the PTO On/Off switch is in the ON position. This will prevent shutdowns that are unwanted when the PTO mode is active. The "PTO Shutdown Timer" can be used to shut down the engine. This shutdown can be used if the driver/operator is using the PTO mode in order to prevent idle shutdown. The "PTO Shutdown Timer" will shut down the engine but the "PTO Shutdown Timer" will not disable the ECM.

Note: It is critical that the operator of the PTO knows the arrangement. The operator must fully understand the setup of the PTO system. It is also critical that the operator of the PTO understands the operation of the system.

Multiple Speed PTO Operation That Uses The" PTO Engine RPM Set Speed Input A" and "PTO Engine RPM Set Speed Input B"

The multiple speed PTO operation that uses the "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B" is available for use with all three PTO configurations. The engine will operate at the "PTO Engine RPM Set Speed A" that is programmed when the PTO Engine RPM Set Speed Input A switch (Input 7 J1/P1-46) and the PTO On/Off switch are ON. The engine will operate at the "PTO Engine RPM Set Speed B" when the PTO Engine RPM Set Speed Input B switch (Input 4 J1/P1-7) or (Input 19 J1/P1-23) and the PTO On/Off switch are ON.

The "PTO Engine RPM Set Speed B" will not operate unless the "PTO Engine RPM Set Speed A" is in the OFF position. The "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B" have priority over all of the other features that are used to control the engine speed during PTO operation. The exception is any circumstance that causes the PTO operation to be disabled.

The Multiple Speed PTO Operation that uses the "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B" requires JULY 1999 or newer Personality Modules.

Illustration 17	g01299029
Illustration 17 shows the configuration for the multiple speed PTO operation. "PTO Set Speed B" can also be connected to J1/P1-7 Input 4. (A) Set/Resume switch (B) PTO On/Off switch (C) PTO switch on lamp (D) PTO Set Speed B On/Off switch (E) PTO Set Speed A On/Off switch (F) ECM side of the vehicle harness connector P1 (G) Harness side of the vehicle harness connector P1 (P1-3) Input sensor common 2 (P1-23) Input 19 (PTO Set Speed B switch) (7) Input 4 can also be used for PTO Set Speed B switch. (P1-30) Output 1 (PTO switch on lamp) (P1-46) Input 7 (PTO Set Speed A switch) (P1-56) Input 1 (PTO On/Off switch)

Illustration 18	g01026722
Illustration 18 shows the schematic for the multiple speed PTO operation that uses the "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B". "PTO Engine RPM Set Speed B" can also be connected to J1/P1-7 Input 4.