Circuit Test C3 - Fuel Pump Circuit
NOTE:
Enter this test only when directed here from CONTINUOUS SELF-TEST procedure. To prevent replacement of good components, be aware that the following non-EEC areas may be at fault: fuel delivery system, ignition system, or intake air cleaner and duct system. This test is intended to diagnose only the following: fuel pump relay ground circuit at ECA.
- Checking System Integrity - Visually check all wiring, harnesses, connectors and components for evidence of damage, overheating, shorting or looseness. If a fault is found, repair as necessary. If no faults are found, go to next step.
- Checking For Open Fuel Pump Relay Circuit - Install breakout box and set VOM on 20-volt scale. Disconnect ECA. With KOEO, measure voltage between test pins No. 22 and 49 at breakout box. If voltage is less than 10 volts, go to next step. If voltage is not to specification, repair open in "LG" wire from fuel pump relay to ECA. Reconnect ECA.
- Checking Harness For Shorts To VREF - Install breakout box and set VOM on 20-volt scale. Disconnect ECA. Remove fuel pump relay. Measure voltage between test pins No. 22 and 20 (ground), and between test pins No. 22 and 49 (ground). If any voltage readings are greater than 10 volts, repair short to VAPWR or KAPWR in wiring harness. Reinstall fuel pump relay. If voltage is not as specified, go to next step.
- Checking ECA Input Voltage - Install breakout box. Leave ECA connected and fuel pump relay installed. Measure voltage between test pins No. 22 and 49 at breakout box with KOEO and KOER (engine at idle). If voltage is greater than 10 volts with engine off, and less than 4 volts at idle, go to DIAGNOSTIC ROUTINES . If readings are not as specified, ensure fuel pump relay and related circuit are okay and replace ECA.