J90 - 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 reset (if in power-to-pump circuit).

- Open circuit in or between the fuel pump and Fuel Pump Monitor (FPM) circuit at the PCM (refer to 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 (with/dual HO2S).

- Engine stall due to excessive load.

NOTE:If KOEO DTC 111 and Continuous DTC 542 is present both times, continue with this test (intermittent concern). If KOEO DTC 542 is present in only one test, refer to the Fuel Delivery and Air Induction/Testing and Inspection to check for open circuit between select switch and suspect pump circuit ground.

- 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 power-to-pump pin at the fuel pump relay 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.

- For vehicles with the Inertia Fuel Shutoff switch in the power-to-pump circuit (refer to schematic), 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 J91. J91 - Check FPM Circuit