KN1 - KOEO Service Code 554: Enter Output State Check

Diagnostic Trouble Code (DTC) 554 indicates a failure in the Fuel Pressure Regulator Control (FPRC) solenoid circuit.

Possible causes:

- Damaged FPRC solenoid.

- Damaged vacuum hose(s).

- Open in harness.

- Short (to power or ground) in harness.

- Damaged Powertrain Control Module (PCM).

NOTE: Do not use STAR Tester for this step. Use a Analog Volt/Ohm Meter (VOM)/Digital Volt/Ohm Meter (DVOM).

- Key "OFF".

- Disconnect electrical connector on the speed control servo, if equipped.

- DVOM on 20 volt scale.

- Connect DVOM negative test lead to Self Test Output (STO) circuit at Data Link Connector (DLC) and positive test lead to battery positive.

- Jumper STI circuit to SIG RTN at DLC.

- Perform Key On Engine Off (KOEO) Self-Test until completion of Continuous Test Memory DTCs. Quick Test Appendix (Detailed Testing Instructions)

- DVOM will indicate less than 1.0 volt when test is completed.

- Depress and release throttle.

- Does voltage increase?

Yes -- Remain in Output State test mode. Go to KN2. KN2 - Fuel Pressure Regulator Solenoid Electrical Operation

No -- Depress throttle to Wide Open Throttle (WOT) and release. If STO voltage does not go high, leave equipment hooked up and go to pinpoint test step QC1. QC1 - Check For Codes 23, 53, 63, 121, 122 or 123