3412E & C30 MARINE ENGINE Caterpillar

Throttle Position Sensor

The Throttle Position Sensor (TPS) eliminates the mechanical throttle and governor linkages. The TPS utilizes the lever movement by the operator to send an electrical signal to the ECM for the engine. The TPS signal and the speed/timing signal are processed by the ECM to control engine speed.

The output of the sensor is a constant frequency signal with a pulse width that varies with the throttle position. The pulse width measures the duty cycle. The Pulse Width Modulated (PWM) signal is expressed as a percentage of the duty cycle.

Figure 20 - Duty Cycle

Figure 21 - PWM Definition

Figure 22 - Throttle Position Percent versus PWM Input

PWM Input Requirements

The following criteria are required for the correct operation of the throttle position sensor:

* Active pull up/ pull down with output protection

* Sensor stop -

Low Stop 7.5 ± 2.5%High Stop 92.5 ± 2.5%.

* Output frequency-

Minimum of 300 HzNominal of 500 HzMaximum of 700 Hz

* High output voltage -

Minimum of 4.5 VDCMaximum of 32.0 VDC.

* Low output voltage

Minimum of -0.3 VDCMaximum of 0.5 VDC

* Sink current

1.5 mA

* Source current

2.0 mA

* Output linearity ±2.5% duty cycle vs. throttle lever position.

Figure 23 - ECM Test Circuit

Engine Synchronization Switch

The purpose of the engine synchronization switch is to link multiple engine ECM's to a single throttle on the vessel. The single throttle controls the engine speed for all the engines. This feature improves the control of the vessel and adds operator convenience.

A single throttle control for vessels that have multiple engines is standard practice which allows the transfer of throttle control to any other throttle.

Table 10: "Code for Synchronization of Throttle Controls" gives the code that determines the synchronization of throttle controls. The synchronization function can only be activated or deactivated when the desired engine speed of all engines are within 50 rpm of each other.

Table 10: Code for Synchronization of Throttle Controls

Multiple Synchronization Switch Installations

These engines support single station throttle synchronization. The synchronization is accomplished by the use of two switch inputs on each ECM to determine the throttle synchronization. The engine ECM is not designed to support synchronization switches from multiple stations.

Multiple stations complicate the wiring and typically require some method of transferring control from one station to another station. The transfer of control may be accomplished by several methods. The boat builder or installer is responsible for determining the method and ensuring proper operation of synchronization.

If multi-station synchronization switches are installed, care MUST be taken to prevent both of the synchronization inputs (Connector J3 pin 34 and pin 35) from being connected to the Negative Battery Bus Bar. If both synchronization inputs are low, the ECM will only monitor the primary throttle and the synchronization inputs will be ignored. Care MUST also be taken to ensure that positive battery to negative battery SHORT CIRCUIT does not occur in the wiring for the synchronization switches.

Throttle Control for Single Engine Installation

Figure 24 - Throttle Position Sensor Connections for a Single Engine Installation

Table 11: Throttle Switch Positions

Table 12: Parts for Single Engine Installation

Synchronization for Two Engines

Figure 25 - Throttle Position Sensor Connections for a Two Engine Synchronization

Table 13: Code for Synchronization of Throttle Controls

Table 14: Parts for Two Engine Installation

Synchronization for Three Engines

Figure 26 - Throttle Position Sensors Connections for Three Engine Synchronization

Synchronization for Four Engines

Figure 27 - Schematic for Connecting Throttle Position Sensors for Four Engine Synchronization

Calibration of Throttle Position Sensor

Calibration of the Throttle Position Sensor requires Cat ET.

Refer to "Troubleshooting", SENR5015 for additional information on calibrating the throttle position sensor.

Throttle Linkage

Inspect the throttle linkage for components that are:

* Loose

* Bent

* Broken

* Missing

* Worn

The throttle linkage should operate without binding or excessive drag. The throttle linkage should automatically return to the position of low idle in less than one second.

Perform the following steps to adjust the throttle linkage:

1. Turn the ignition switch to the OFF position.

2. Connect the Cat ET to the service tool connector.

3. Turn the ignition switch to the ON position. Do not start the engine.

4. Observe the indicator for duty cycle on the Monitor Throttle Position Sensor Signal screen of the Electronic Service Tool.

5. Place the throttle lever in the position for low idle. Adjust the throttle linkage.

When in low idle, the duty cycle should indicate between 5 and 10 percent. When the throttle lever is moved from the position of low idle after the adjustment is completed, the duty cycle should increase.

6. Place the throttle lever in the position of high idle. Adjust the throttle linkage.

When in high idle, the duty cycle should indicate between 90 and 95 percent. When the adjustment of high idle is made on some types of linkage, that adjustment may change the low idle position. Repeat the adjustment for low idle to verify that the low idle is correctly adjusted.

Remote Shutdown Switch

When the Remote Shutdown Switch closes, the ECM disables the fuel injection signal. This action causes the engine to shut down. The ECM remains powered and active.

Table 15: Parts Required for Installation of Remote Shutdown Switch

Figure 28 - Connection for Remote Shutdown Switch

Trolling Mode Input

When the Trolling Mode is in operation, the full range travel of the throttle lever causes the engine speed to change from low idle to the maximum programmed trolling speed. The Trolling Mode only engages if the engine speed is within 30 rpm of low idle. Trolling Mode can also be activated when the engine is shut down.

When the transmission is in Trolling Mode, the switch input for the Trolling Mode is connected to the Negative Battery Bus Bar. The activation of the trolling valve must automatically connect the switch input of the Trolling Mode to the Negative Battery Bus Bar.

Table 16: Parts Required for Installation of Trolling Mode Actuation

Figure 29 - Connection for the Trolling Mode Actuation

A physical switch does not exist for the trolling valve actuation. When the trolling valve is activated, the circuit is automatically completed.

Slow Vessel Mode Switch

When the slow vessel mode switch closes. the ECM reduces the programmed low idle to 550 rpm. This feature improves the maneuverability of the vessel in docking and no wake zones.

Table 17: Parts Required for Installation of the Slow Vessel Mode Switch

Figure 30 - Connection for the Slow Vessel Mode Switch

Trip Clear Switch

When the Trip Clear Switch is activated, the ECM clears the trip data. Then, the ECM starts a new trip log. This action clears the trip histograms and the trip total. The lifetime totals are not cleared.

Table 18: Parts Required for Installation of the Trip Clear Switch

Figure 31 - Connection for Trip Clear Switch

ECM Driven Warning Alarm and Diagnostic Lamps

The ECM provides drivers capable of sinking or sourcing 300mA, which can be used to drive a relay or audible/visual alarms to indicate various diagnostic conditions.

Driver Specifications

Electrical specifications for the ECM low side and high side drivers used for the Diagnostic Lamp and Warning/Alarm Lamps allow a maximum load current of 0.30 amperes (300mA). The ECM does not provide diagnostic codes associated with either lamp circuit.

Figure 32 - Low Side Driver (Sinking Driver)

Low side ECM drivers provide a path to the -Battery Bus Bar to activate a lamp or other device connected to it. Caterpillar, Inc. does not require dedicated circuit protection for these circuits.

Figure 33 - High Side Driver (Sourcing Driver)

High side ECM drivers provide a path to +Battery to activate a lamp or other device connected to it. Caterpillar, Inc. does not require dedicated circuit protection for these circuits.

Diagnostic Lamp Operation

The Diagnostic Lamp alerts the operator to the presence of active diagnostic codes. A diagnostic code indicates a fault condition in the electronic control system. The operator uses this indication to diagnose component failures in the electronic control system.

Viewing Diagnostic Flash Codes

Caterpillar has developed a proprietary two digit diagnostic flash code. The two digits can be determined by observing the Diagnostic Lamp. The lamp will flash to identify the flash code. The flash code identifies active codes that have occurred after the ECM is energized.

A diagnostic lamp installed by an OEM is required to indicate a diagnostic condition flash code to the operator.

Determine the flash code by the following procedure:

1. Count the flashes on the Diagnostic Lamp to determine the first digit.

2. A two second pause will occur before the lamp flashes for the second digit.

3. Count the flashes to determine the second digit.

4. If more than one diagnostic condition has occurred, all of the active codes that have been received since the ECM was energized will be displayed. The two digit code for each diagnostic condition will flash with a five second pause between the flash codes.

The diagnostic flash codes should only be used to indicate the nature of the occurrence of a diagnostic condition. The flash codes should not be used to perform detailed troubleshooting. Troubleshooting should be performed using SAE J1587 CID/FMI diagnostic codes that are determined by an Electronic Service Tool.

Warning Lamp Operation

The Caterpillar electronic monitoring system offers optional warning lamps that can be installed by the OEM. These warning lamps alert the operator to the occurrence of several fault conditions that are detected by the ECM. The prompt observance of these fault conditions by the operator provides greater protection of the engine.

The following procedure determines if the Warning Lamp circuit is functional:

1. Turn the ignition switch to the ON position. Do not start the engine. When the switch is in the ON position, the ECM is energized.

2. The ECM will turn the Warning Lamp on for five seconds.

3. If the lamp circuit functions correctly, the Warning Lamp will turn off unless a fault condition exists.

An OEM installed Warning Lamp is required to indicate a potentially engine damaging problem determined by the electronic monitoring system.

Warning Indicator Lamp or Alarm

The lamp or alarm alert the operator that a fault condition has occurred. If the following events occur, the Warning Lamp or the audible alarm, if equipped, are activated:

* An event code is active.

* The engine is in the derate mode.

When the ECM is energized, the warning indicator lamp will turn on for five seconds. Then, the lamp will turn off unless the ECM detects that an engine event is active.

Low Oil Pressure Lamp

The low oil pressure lamp indicates the occurrence of low oil pressure. This diagnostic is determined by the ECM based upon the relationship between the engine speed and the actual oil pressure.

When the ECM is energized, the low oil pressure lamp will turn on for five seconds. Then, the lamp will turn off unless the ECM detects a low oil pressure condition.

High Coolant Temperature Lamp

The high coolant temperature lamp indicates the occurrence of high coolant temperature.

When the ECM is energized, the high coolant temperature lamp will turn on for five seconds. Then, the lamp will turn off unless the ECM detects a high coolant temperature condition.

Low Coolant Level Lamp

The low coolant level lamp indicates the occurrence of low coolant level.

When the ECM is energized, the low coolant level lamp will turn on for five seconds. Then, the lamp will turn off unless the ECM detects a low coolant level condition.

Warning Lamp Installation

Figure 34 - Schematic of Warning Lamps and Alarms

Table 19: Parts for Warning Lamp Installation

Warning Alarms Requiring More Than 300 Milliamperes

Figure 35 - Schematic for Warning Lamps and Alarms Requiring More Than 300 Milliamperes.

Hour Meter (Optional)

The ECM provides a signal for the hour meter. When the ECM reads an engine speed that is greater than 500 rpm, the ECM turns on the hour meter. This signal is actual is actual engine hours.

Table 20: Parts Required for Installation of the hour meter

Figure 36 - Connections for Hour Meter

Maintenance Indicator Mode

Factory Default:OFF

Programming Range:OFF, Manual Hours, Manual Fuel, Auto Fuel, and Auto Hours

Function:Allows customer to turn maintenance indicator off or on. Determines whether maintenance interval will be displayed as fuel or hours. In manual mode, the user may define user interval for PM1.

Maintenance Indicator PM1 Interval

*OFF -Default

*Manual Hours -The number of engine hours to service.

*Manual Fuel -The number of gallon of fuel to service.

*Auto Hours -The ECM automatically calculates time to service based on recorded fuel consumption and oil sump capacity.

If PM1 is programmed to automatic, the ECM calculates the next maintenance due by considering the engine operation history from the previous maintenance interval. If the engine has a history of poor fuel economy, the maintenance indicator will occur sooner than it would on an engine with better fuel economy.

Maintenance Indicator PM2 Interval

Factory Default:2500 hours, manual hours mode. 94635 L (25000 gal), manual fuel mode.

Programming Range:N/A

Function:Defines the hour or fuel interval for PM2 if the manual maintenance mode is selected.

Maintenance Indicator PM3 Interval

Factory Default:3000 hours, manual hours mode. 113562 L (30000 gal), manual fuel mode.

Programming Range:N/A

Function:Defines the hour or fuel interval for PM3 if the manual maintenance mode is selected.

Maintenance Indicator Lamp

When the preventive maintenance interval occurs, such as PM Level 1, the maintenance indicator lamp turns on.

When running against the fuel to air ratio control map, the lamp turns on for 90 seconds.

When the ECM is energized, the maintenance indicator lamp will turn on for five seconds. Then, the lamp will turn off unless the ECM detects that a maintenance interval has occurred.

Maintenance Clear Switch (Optional)

The maintenance clear switch is required to reset the PM1 diagnostic for the maintenance indicator after maintenance on the engine is performed. The maintenance clear switch is standard equipment on the engine mounted control panel. The installation of the switch is optional.

Table 21: Parts Required for Installation of the Maintenance Clear Switch

Figure 37 - Connection for Maintenance Clear Switch