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Home >> Ford >> 1992 >> Crown Victoria Base, AOD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Tests W/Codes - EEC-IV >> Circuit Tests >> Circuit Test Kn - Fuel Pressure Regulator Control (FPRC) Solenoid >> Diagnostic Aids

Diagnostic Aids

Perform this test when instructed during QUICK TEST  . Use this test only to diagnose:

To prevent replacement of good components, be aware following non-EEC areas may be cause of driveability concerns:

Fig 1: Fuel Pressure Regulator Control (FPRC) Solenoid Circuit
G92H03870

1) Code 554: Enter OUTPUT STATE CHECK  Code 554 indicates fault in FPRC circuit. Possible causes are:

Use only VOM or DVOM for this step. DO NOT use scan tester. Turn ignition off. Disconnect cruise control servo wiring harness connector. Connect DVOM negative lead to STO terminal at Self-Test connector. Connect positive lead to positive battery terminal. Install a jumper wire between STI terminal and SIG RTN terminal at self-test connector. See Figure in CIRCUIT TEST QA. Perform KOEO SELF-TEST  until continuous memory test is complete. DVOM will read less than 1.0 volt when test is complete to indicate ECA has entered OUTPUT STATE CHECK. Depress and release throttle. If voltage increases, remain in OUTPUT STATE CHECK and go to step 2). If voltage does not increase, depress throttle to WOT and release. If voltage increase, remain in OUTPUT STATE CHECK and go to step 2). If voltage does not increase, leave test equipment connected and go to CIRCUIT TEST QC.

2) Check FPRC Solenoid Operation  Disconnect FPRC solenoid. Turn ignition on. Connect DVOM positive lead to VPWR terminal and negative lead to FPRC terminal at FPRC solenoid wiring harness connector. Observe DVOM while depressing and releasing throttle 3-5 times. If FPRC solenoid output voltage varies 1.0 volt or less, go to step 5). If FPRC solenoid output voltage varies more than 1.0 volt, go to step 3).

3) Check FPRC Vacuum Signal  Disconnect and inspect FPRC vacuum hose. Repair or replace if necessary. Start engine, and warm it to normal operating temperature. Turn ignition off. Connect vacuum gauge between FPRC solenoid and fuel pressure regulator. Start engine. If vacuum is present, replace FPRC solenoid. If vacuum is not present, remove vacuum gauge and go to step 4).

4) Check Manifold Vacuum Source  Ensure engine is warmed to normal operating temperature. Turn ignition off. Connect vacuum gauge between FPRC solenoid and manifold vacuum source. Start engine. If vacuum is present, replace FPRC solenoid. If vacuum is not present, replace vacuum hose.

5) Check FPRC Solenoid VPWR  Turn ignition off. Disconnect FPRC solenoid wiring harness connector. Measure voltage between VPWR terminal at FPRC wiring harness connector and negative battery terminal. If voltage is less than 10.5 volts, repair open circuit. If voltage is 10.5 volts or more, go to step 6).

6) Check Continuity Of FPRC Circuit  Turn ignition off. Disconnect 60-pin ECA connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving ECA disconnected. Disconnect FPRC solenoid wiring harness connector. Measure resistance between breakout box test pin No. 13 and FPRC terminal at solenoid wiring harness connector. If resistance is 5 ohms or less, repair open circuit. If resistance is more than 5 ohms, go to step 7).

7) Check FPRC Circuit For Short  Turn ignition off. Disconnect FPRC solenoid wiring harness connector. Measure resistance between breakout box test pin No. 13 and test pins No. 37 and 57. Measure resistance between breakout box test pin No. 13 and test No. 40, 46 and 60. If any resistance is 10,000 ohms or less, repair short circuit and repeat QUICK TEST  . If each resistance is more than 10,000 ohms, replace ECA and repeat QUICK TEST.

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