X165 - Check For VPWR to Low Speed Fuel Pump Relay

DTC Diagnostic Trouble Code (DTC) 557 indicates a low speed fuel pump primary circuit failure.

Possible causes:
- Open or shorted circuit.
- Damaged Low Speed Fuel Pump (LFP) relay.
- Damaged Powertrain Control Module (PCM).

- Disconnect LFP relay.

- Key "ON", engine "OFF".

Low Fuel Pump (LFP) Relay Connector:

- Measure voltage between the VPWR circuit at the LFP relay vehicle harness connector and the battery negative post.

- Key "OFF".

- Was voltage greater than 10.5 volts?

Yes -- Go to X166. X166 - Check LFP Relay

No -- Service open in VPWR circuit between Constant Control Relay Module (CCRM) and LFP relay. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)