P1491

Tests 1 - 3:

Tests 4 - 7:

SYMPTOM
P1491 - RADIATOR FAN CONTROL RELAY CIRCUIT

WHEN MONITORED
With the ignition key ON, battery voltage greater than 10.0 volts and the PCM requests the radiator fan to be turned ON.

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

POSSIBLE CAUSES
- Radiator fan control relay circuit wire harness intermittent problem
- Radiator fan control relay circuit wire harness observable problem
- Radiator fan relay control circuit open
- Radiator fan relay control circuit shorted to ground
- Fused ignition switch output open
- PCM
- Radiator fan control relay