XB120 - KOEO Code 542: Will Engine Start and Idle

Key On Engine Off Diagnostic Trouble Code (DTC) 542 indicates that one of the following has occurred:

No Start:

- Inertia Fuel Shutoff (IFS) switch not reset or electrically open.

- Open in power-to-pump circuit between the Fuel Pump Monitor (FPM) splice and the fuel pump.

- Poor fuel pump ground.

- Open circuit in fuel pump.

Engine Starts:

- Power-to-pump/FMP circuit short to power.

- High Speed Fuel Pump (HFP) relay contacts stuck closed.

- HFP circuit (Variable Control Relay Module (VCRM) Pin 10) short to ground.

- Open FPM circuit between PCM and power-to-pump splice.

- Left Heated Oxygen Sensor (HO2S) short to power.

- Damaged VCRM.

- Damaged PCM.

- Will the engine start and idle for one minute?

Yes -- Go to XB121. XB121 - Verify That Fuel Pump Is Off

No -- Go to XB130 (to check for open in power-to-pump circuit between FPM splice and fuel pump ground. XB130 - Check Inertia Fuel Shutoff (IFS) Switch

If engine starts but stalls, open is between FPM splice and HFP relay splice).