X105 - Continuous Code 542: Check EEC-IV Harness

A Continuous Memory Diagnostic Trouble Code (DTC) 542 indicates that one of the following intermittent conditions has occurred:

- Fuel pump circuit activated when Powertrain Control Module (PCM) expected circuit to be off (i.e. fuel system test or prime procedure).

- Inertia Fuel Shutoff switch was tripped, then reset.

- Open circuit in or between the fuel pump and Fuel Pump Monitor (FPM) circuit at the PCM (refer to schematic). X - Testing Schematic

- Poor fuel pump ground.

- FPM or power-to-pump circuit short to power.

- Fuel pump relay contacts stuck closed.

- Left/Front Heated Oxygen Sensor (HO2S) circuit short to power (w/dual HO2S).

- Engine stall due to excessive load.

- Start engine.

- Check for engine stall/stumble while performing the following (also, if possible, listen for fuel pump turning off):

- Shake, wiggle, bend the Power-To-Pump circuit between the Constant Control Relay Module (CCRM) Pin 5 and the fuel pump.

- Shake, wiggle, bend the fuel pump ground circuit from the fuel pump to ground.

- Lightly tap the fuel pump to simulate road shock.

- Lightly tap Inertia Fuel Shutoff switch to simulate road shock.

- Key "OFF".

- Inspect the fuel pump vehicle harness connector and the fuel pump ground for corrosion, damaged pins, etc.

- Is fault indicated/found?

Yes -- Isolate fault and service as necessary. Clear continuous memory DTC. Clearing Diagnostic Trouble Codes

Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

No -- Go to X106. X106 - Check FPM Circuit