DTC 51: Injector Circuit
- Check Control Function
- For California models, go to step 2). Start engine. Measure voltage between engine ground and following ECM terminals. See Figure.
- No. 101 For No. 1 Cylinder
- No. 103 For No. 3 Cylinder
- No. 105 For No. 5 Cylinder
- No. 110 For No. 2 Cylinder
- No. 112 For No. 4 Cylinder
- No. 114 For No. 6 Cylinder
If battery voltage is present at each terminal, injector circuit is okay. If battery voltage is not present at each terminal, go to next step.
- Check Power Supply
- Turn ignition off. Disconnect sub-harness connectors for injectors No. 1, 3 and 5. Disconnect wiring harness connector for fuel injectors No. 2, 4 and 6. See Fig 1. Turn ignition on. Measure voltage between following terminals. See Fig 2.
- Fuel injector wiring harness connector terminal "a" (Yellow wire) and ground.
- Fuel injector sub-harness connector terminal "d" (Yellow wire) and ground.
- ECM wiring harness connector terminal 46 (Yellow wire) and ground. See Figure.
If battery voltage is present, go to next step. If battery voltage is not present, repair open or short circuit in wiring harness or blown 25-amp fusible link.
- Check Output Signal
- Turn ignition off. Disconnect ECM wiring harness connector. See Figure. For fuel injectors No. 2, 4 and 6, check continuity between following terminals. See Fig 3.
- Fuel injector wiring harness connector terminal "b" and ECM connector terminals No. 110, 112 and 114.
For fuel injectors No. 1, 3 and 5, check continuity between following terminals. See Fig 3.
- ECM connector terminal No. 101 and fuel injector wiring harness connector terminal "b".
- ECM connector terminal No. 103 and fuel injector wiring harness connector terminal "c".
- ECM connector terminal No. 105 and fuel injector wiring harness connector terminal "g".
If continuity is present, circuit is okay. Go to next step. If continuity is not present, repair harness or connectors as necessary.
- Check Component - Release fuel pressure. Remove fuel injector assembly. See N REMOVE/INSTALL/OHAUL article in the ENGINE PERFORMANCE section. Inspect fuel injectors. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Replace fuel injector(s) if necessary and perform FINAL CHECK in this article. If all fuel injectors are okay, repair ECM pin terminals and/or wiring harness connector.