P1491 Rad Fan Control Relay Circuit

SYMPTOM
P-1491 RADIATOR FAN CONTROL RELAY CIRCUIT

WHEN MONITORED
With the ignition on, battery voltage greater than 10 volts, and the PCM requests the fans be on.

SET CONDITION
An open or shorted condition is detected in the radiator fan relay control circuit.

POSSIBLE CAUSES
- Fan relay ground circuit open
- Fused B(+) circuit open
- Rad fan control relay defective
- RF relay output ckt volt cycles over to batt volt
- Rad fan relay control circuit open
- Radiator fan ctrl rly ckt wir harn observable def
- Radiator fan ctrl rly ckt wiring harness inter def
- Radiator fan relay control circuit short to ground
- PCM defective