X111 - Check EEC-IV Harness

A Continuous Memory Diagnostic Trouble Code (DTC) 524/543, without the presence of a Continuous Memory DTC 556/557, 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 Constant Control Relay Module (CCRM) / LFP relay to the Fuel Pump Monitor (FPM) splice.

- Left/Front Heated Oxygen Sensor (HO2S) circuit short to power (w/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 fuel pump relay B(+) circuit to the CCRM/LFP relay.

- Lightly tap the CCRM/LFP relay (to simulate road shock).

- Shake, wiggle, bend the power-to-pump circuit from the CCRM/LFP relay to the FPM splice.

- Key "OFF".

- Inspect the CCRM/LFP relay connector 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 524/543 may have been set without a Continuous Memory DTC 556/557, even though a fault has occurred in the fuel pump primary circuit. Go to X115 to check the fuel pump primary circuit. X115 - Continuous Code 556/557: Check EEC-IV Harness>