J94 - Check EEC-IV Harness

A continuous memory Diagnostic Trouble Code (DTC) 543, without the presence of a continuous memory DTC 556, indicates that during vehicle operation one of the following has occurred:

- Open in the B(+) circuit between B(+) and the fuel pump relay.

- Fuel pump relay contacts opened.

- Open in the power-to-pump circuit from the fuel pump relay to the Fuel Pump Monitor (FPM) splice, if applicable (refer to schematic). J - Testing Schematic

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

- Start engine.

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

- Shake, wiggle, bend the B(+) circuit from B(+) to the fuel pump relay.

- Lightly tap the fuel pump relay (to simulate road shock).

- Shake, wiggle, bend the power-to-pump circuit from the fuel pump relay to the FPM splice, if applicable (refer to schematic). J - Testing Schematic

- Key "OFF".

- Inspect the fuel pump relay connectors and B(+) connector terminal for corrosion, damaged pins, etc.

- Is fault indicated/found?

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

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

No -- Under certain conditions, a continuous memory DTC 543 may have been set without a continuous memory DTC 556, even though a fault has occurred in the fuel pump rimary circuit. Go to J95 to check the fuel pump primary circuit. J95 - Check EEC-IV Harness