XB162- Check VCRM and HFP Circuit Operation

- Key "OFF".

- Reconnect High Speed Fuel Pump (HFP) relay.

- Start and run engine to warm to normal operating temperature.

- Key "OFF".

- Disconnect HFP relay.

- Connect Digital Volt/Ohm Meter (DVOM) between the B(+) circuit and the HFP circuit at the HFP relay vehicle harness connector.

- All accessories "OFF" (radio, A/C, etc.)

- Start engine and let idle. Within 10 seconds of the start, note DVOM voltage.

- Does the voltage decrease at least 0.4 volts from the first reading within 2 minutes of the start?

NOTE: The HFP circuit output from the Variable Control Relay Module (VCRM) should be grounded during the initial start, but will unground within 2 minutes of the start. The exact amount of time the circuit is grounded is coolant temperature dependent.

Yes -- Key "OFF". VCRM and HFP circuits are OK. Go to XB163 (to check HFP relay). XB163 - Check HFP Relay Operation

No -- Key "OFF".Go to XB165 (to check HFP circuit). XB165 - Check HFP Circuit Continuity