79139A 5 Mercruiser WIRE, 90 AMP FUSE TO CIRCUIT BREAKER

Table 1
J1939 Codes and Description Comments
3675-8
Engine Turbocharger Compressor Bypass Actuator Position : Abnormal Frequency, Pulse Width, or Period The actuator has detected an error in the Pulse Width Modulated (PWM) signal that is from the Electronic Control Module (ECM).
The code is logged.
The engine is shutdown.
5420-12
Engine Turbocharger Compressor Bypass Actuator #1 : Failure During a self-test the actuator has detected an internal fault.
The code is logged.
The engine is shutdown.
3470-8
Engine Turbocharger Compressor Control : Abnormal Frequency, Pulse Width, or Period The actuator has detected an error in the Pulse Width Modulated (PWM) signal that is from the Electronic Control Module (ECM).
The code is logged.
The engine is shutdown. Note: For a 3675-9 Engine Turbocharger Compressor Bypass Actuator Position : Abnormal Update Rateor 3470-9 Engine Turbocharger Compressor Control : Abnormal Update Rate refer to Troubleshooting , CAN Data Link - Test for information that is related to troubleshooting the data link circuitry.
Illustration 1 g06389032
For the complete circuit details, refer to the full schematic.
Table 2
Troubleshooting Test Steps Values Results
1. 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: A -8 code is active or logged.
Proceed to Test Step 2.
Result: A 5420-12 code is active or logged.
Repair: The turbocharger compressor bypass actuator has detected an internal problem with the actuator electronics. Replace the compressor bypass actuator.
2. 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 3.
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 3.
3. Check the Wiring for an Open Circuit
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the A-C1 and A-C2 wiring harness connectors from the ECM.
C. Disconnect the turbocharger compressor bypass actuator connector.
D. Measure the resistance between the following locations:
- Terminal 18 (PWM +) of the compressor bypass actuator connector and terminal 3 of the A-C2 ECM connector.
- Terminal 10 (PWM -) of the compressor bypass actuator connector and terminal 5 of the A-C1 ECM connector.
Open Circuit
Result: Both measurements were less than 10 ohms between the connector terminals.
Proceed to Test Step 4.
Result: One or more of the measurements were greater than 10 ohms between the connector terminals.
Repair: An open circuit has been detected. Repair or replace the wiring harness.
If the problem is not resolved, proceed to Test Step 4.
4. Check the Wiring for a Short Circuit to Engine Ground
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the A-C1 and A-C2 wiring harness connectors from the ECM.
C. Disconnect the turbocharger compressor bypass actuator connector.
D. Measure the resistance between the following locations:
- Terminal 18 (PWM +) of the turbocharger compressor bypass actuator connector and engine ground.
- Terminal 10 (PWM -) of the turbocharger compressor bypass actuator connector and engine ground.
Short Circuit
Result: Both measurements were greater than 100 K ohms between a turbocharger compressor bypass actuator connector terminal and engine ground.
Proceed to Test Step 5.
Result: One or more of the measurements were less than 100 K ohms between a turbocharger compressor bypass actuator connector terminal and engine ground.
Repair: There is a short circuit in the wiring harness. Repair or replace the wiring harness.
If the problem is not resolved, proceed to Test Step 5.
5. Check the Wiring for a Short Circuit
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the A-C1 and A-C2 wiring harness connectors from the ECM.
C. Disconnect the turbocharger compressor bypass actuator connector.
D. Measure the resistance between the following locations:
- Connector A-C2 terminal 3 (PWM +) and all other terminals of the ECM connector.
- Connector A-C1 terminal 5 (Digital Return) and all other terminals of the ECM connector.
Short Circuit
Result: One or more of the measurements were less than 100 K ohms between a connector terminals and any other terminal in the ECM connector.
Repair: There is a short circuit in the wiring harness. Repair or replace the wiring harness.
Verify that the repair eliminated the problem.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).