Series 60 DDEC V Troubleshooting – Section 4.1 Electronic Control Unit Wiring Harness

Section 4.1
Electronic Control Unit Wiring Harness

To determine if the Electronic Control Unit (ECU) Vehicle Interface Harness (VIH) is causing starting difficulty, perform the following steps:‪

1. Turn the ignition switch to the on position.
2. Install the Diagnostic Data Link (DDL) adaptor to the data cable and plug the adaptor into the DDL connector in the vehicle; refer to OEM guidelines.
3. Determine if ECU data is being received by the DDR; refer to OEM guidelines.
   1. If no data is being received by the DDR, check for intermittent code or a fault and no codes, refer to "20.1 Intermittent Code or a Symptom and No Codes" .
   2. If data is being received by the DDR, check vehicle circuit breakers or fuses; refer to "4.1.1 Vehicle Circuit Breakers or Fuses Check" .

Section 4.1.1
Vehicle Circuit Breakers or Fuses Check

To determine if the vehicle circuit breakers are causing starting difficulty, perform the following steps: ‪

1. Visually check ECU circuit breakers or fuses.
2. Determine if circuit breaker(s) or fuse(s) are tripped or blown; refer to OEM guidelines.
   1. If circuit breakers tripped, determine cause and repair or replace as necessary; refer to OEM guidelines. Perform validation; refer to "4.1.3.1 Test Engine with Repaired Harness" .
   2. If circuit breakers are not tripped, measure the voltage at the ECU power harness; refer to "4.1.2 VIH Troubleshooting" .

Section 4.1.2
VIH Troubleshooting

To determine if the VIH is causing circuit breakers to be tripped or blown, refer to "80 Vehicle Interface Harness" and troubleshoot the VIH.‪

Section 4.1.3
Vehicle Interface Harness Repair

Perform the following steps to repair the VIH:‪

1. Repair damage to the VIH.
2. Verify repair of the VIH; refer to "4.1.3.1 Test Engine with Repaired Harness" .

Section 4.1.3.1
Test Engine with Repaired Harness

Perform the following steps to determine if the repair resolved starter difficulty:‪

1. If the engine starts and runs, no further troubleshooting is required. Shut down the engine.
2. If the engine fails to start and run, check for empty fuel tank; refer to "4.2 Empty Fuel Tank" .