Diagnosis & Repair Procedure
- If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK under SYSTEM TESTS.
- Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM harness connector E92 terminal No. 3 (Orange/Black wire). See Figure . When engine coolant temperature is less than 200°F (93°C), reading should be 10-14 volts. When engine coolant temperature is 208°F (98°C) or more, reading should be 0-2 volts. If voltages are as specified, problem is probably intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. If intermittent problem is not found, substitute a known good ECM, and repeat DTC CONFIRMATION TEST . If voltages are not as specified, go to next step.
- Turn ignition off. Remove radiator cooling fan relay from engine compartment fuse/relay block at located left side of engine compartment. See Figure . Check cooling fan relay socket cavities and relay terminals for clean tight connections. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem is found, go to next step.
- Using DVOM, measure resistance between cooling fan relay terminals No. 3 and 4. See Figure . Resistance should be 70-110 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace cooling fan relay. After repair, repeat DTC CONFIRMATION TEST .
- Check for open or short in Black/White wire between radiator cooling fan relay and ignition switch. See WIRING DIAGRAMS article. Also, check for open or short in Orange/Black wire between radiator cooling fan relay and ECM. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem with wiring is found, go to next step.
- Substitute a known good ECM, and retest system. After repair, repeat DTC CONFIRMATION TEST . If DTC does not reset, testing is complete.