XB144 - Does Engine Start With HFP Relay Disconnected

- Key "OFF".

- Disconnect High Speed Fuel Pump (HFP) relay (located in Power Distribution Box).

- Attempt to start engine and run for one minute.

- Does the engine start and run for one minute?

Yes -- Reconnect HFP relay. Go to XB127 (to check left Heated Oxygen Sensor (HO2S) for short to power). XB127 - Check Left HO2S For Short to Power

No -- Go to XB145. XB145 - Check For B+ to VCRM (Pins 4 and 5)