Circuit Test D7 - Pressure Regulator Control (PRC)
NOTE:
Enter this test only when a Code 25 is displayed during the QUICK TEST procedure. To prevent replacement of good components, be aware that the following non-EEC areas may be at fault: vacuum leaks or fuel pressure regulator. This test is intended to diagnose only the following: PRC solenoid, ECA and wiring harness circuits (PRC and VPWR).
- 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 Voltage At ECA - Install breakout box and disconnect ECA. Set VOM on 20-volt scale. Turn key on and wait 2 minutes. Measure voltage between test pins No. 31 and 20 (ground). If voltage is less than 10 volts, go to next step. If not, go to step 6).
- Checking Voltage From PRC Solenoid - Disconnect ECA. Leave PRC solenoid connected and set VOM on 20-volt scale. DO NOT pierce wire during testing. Turn key on and wait 2 minutes. Measure voltage at "W/R" wire between PRC solenoid and ground. If voltage is less than 10 volts, go to next step. If not, repair "W/R" wire between ECA and PRC solenoid.
- Checking Voltage To PRC Solenoid - Disconnect ECA and set VOM on 20-volt scale. With KOEO, measure voltage between "R/BK" wire at PRC solenoid and ground. If voltage is less than 10 volts, go to next step. If not, replace PRC solenoid.
- Checking Voltage From Power Relay No. 2 - Ensure power relay is connected. Set VOM on 20-volt scale. DO NOT pierce wire during testing. With KOEO, measure voltage between "R/BK" wire at power relay No. 2 and ground. If voltage is less than 10 volts, go to CIRCUIT TEST B12 , step 1). If voltage is greater than 10 volts, repair "R/BK" wire between EGR solenoid and power relay No. 2.
- Checking PRC Circuit For Shorts To VPWR - Install breakout box. Disconnect PRC solenoid at harness connector. Disconnect ECA and set VOM on 20-volt scale. With KOEO, measure voltage between test pins No. 31 and 20 (ground). If voltage reading is above zero volts, repair short to VPWR. If not, replace ECA.