70125A 1 Mercruiser COVER, CHOKE

Table 1
J1939 Code and Description Comments
29-3
Accelerator Pedal Position #2 : Voltage Above Normal The Electronic Control Module (ECM) has detected that the analog "0-5 Volt" desired speed signal has exceeded the 4.5 volt trip point.
The setting for the upper diagnostic limit has been exceeded for .6 seconds.
The code is logged.
29-4
Accelerator Pedal Position #2 : Voltage Below Normal The ECM has detected that the analog "0-5 Volt" desired speed signal is below the .5 volt trip point.
The setting for the lower diagnostic limit has been exceeded for .6 seconds.
The code is logged.
974-5
Remote Accelerator Pedal Position : Current Below Normal The ECM has detected a low current in the circuit for the "4-20 mA" desired speed signal.
The current is less than 2 mA for more than 5 seconds.
The code is logged.
The alarm output is activated.
974-6
Remote Accelerator Pedal Position : Current Above Normal The ECM has detected an excessive current in the circuit for the "4-20 mA" desired speed signal.
The current has exceeded 22 mA for more than 5 seconds.
The code is logged.
The alarm output is activated. For this troubleshooting procedure, the "Desired Speed Input" configuration parameter can be set to "4 - 20 mA" input, "0-5 Volt" input, or "CAN"input.If an external speed control source device is used, refer to that devices troubleshooting procedure.If using the Human Machine Interface (HMI) display or other CAN equipped speed control device that supplies a CAN desired speed input, refer to Troubleshooting, "Data Link - Test".The value of the current, frequency, or voltage corresponds to a range of desired engine speeds between minimum high idle and maximum high idle. The "Minimum Engine High Idle Speed" and the "Maximum Engine High Idle Speed" are set with the "Service/Configuration" screen of Cat ET. For more information, refer to Troubleshooting, "Configuration Parameters".When the idle/rated speed switch is in the IDLE position, a current value of 4.0 mA or .5 Volts corresponds to the programmed "Minimum Engine High Idle Speed". A current value of 20.0 mA or 4.5 Volts corresponds to "Maximum Engine High Idle Speed". Desired speed input values within this range will vary the desired engine speed in a linear fashion between. The range will vary between "Minimum Engine High Idle Speed" and "Maximum Engine High Idle Speed".The local/remote engine speed control HMI feature allows the user to select between the available desired speed input configuration options. The Local (CAN) desired speed input configuration selection allows for the user to make engine speed changes from the HMI display. If using the Local (CAN) desired speed input selection, the speed control menu icon allows the user to raise or lower the engines desired speed set point by using the RPM (-) or RPM (+) icons in 10 RPM increments or the user can select one of the preset speeds based on the Cat ET configurable set points for maximum or minimum high idle engine speed or low idle. If the user selects "Remote 4-20 mA Input" or "Remote (0-5 VDC)" input, the RPM (-) and RPM (+), Max High Idle, and Low Idle buttons are disabled as the speed input is now coming from an external source, outside of the operating interface controls of the display.The most likely causes of a diagnostic code for this circuit are a poor connection or a problem in a wiring harness. The next likely cause is a problem with a component. The least likely cause is a problem with the ECM.
Illustration 1 g06302034
For the complete circuit details, refer to the full schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.
C. Perform a 45 N (10 lb) pull test on the connector wires.
D. Check the harness for abrasions and pinch points.
Connectors and Wiring
Result: The connectors and wiring appear to be OK.
Proceed to Test Step 2.
Result: There is a problem with the connectors and/or wiring.
Repair: Repair or replace the connectors or wiring. Ensure that all the seals are properly in place and ensure that the connectors are coupled.
If the problem is not resolved, proceed to Test Step 2.
2. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: Any of the following codes are active or logged:
- 29-4
Proceed to Test Step 3.
Result: Any of the following codes are active or logged:
- 29-3
- 974-6
Proceed to Test Step 7.
Result: A 974–5 code is active or logged:
Proceed to Test Step 9.
3. Check the Wiring for an Open Circuit
A. Ensure that the engine control is in the OFF/RESET position. Ensure that the electrical power is removed from the engine and the speed control device.
B. Disconnect the C-C1 connector from the ECM Box.
C. Disconnect the FA-C3 connector from the ECM.
D. Measure the resistance between the following terminals:
- For the 29-4 code, terminal 94 of the FA-C3 ECM connector and terminal 15 of the FA-C4 connector.
Open Circuit
Result: The resistance measured less than 10 ohms.
Proceed to Test Step 4.
Result: The resistance measured more than 10 ohms.
Repair: An open circuit has been detected. Repair or replace the wiring harness.
4. Check the Wiring for a Short Circuit to Engine Ground
A. Measure the resistance between the ground strap for the ECM and the following terminals at the ECM connector.
- For the 29-4 code, terminal 94 of the FA-C3 ECM connector
Short Circuit
Results: The resistance measured more than 100k ohms.
The signal wire is not shorted to the engine ground.
Proceed to Test Step 5.
Results: The resistance measured less than 100k ohms.
The signal wire is shorted to the engine ground.
Repair: Repair or replace the wiring harness.
5. Check the Wiring Harness for a Pin to Pin Short Circuit
A. Measure the resistance between the following ECM connector
terminals:
- For the 29-4 code, terminal 94 of the FA-C3 ECM connector and all other terminal in the FA-C3 ECM connector.
Short Circuit
Results: One or more of the measurements were less than 100 K ohms between the affected signal wire terminal and any other terminal in the ECM connector.
There