P1490

Tests 1:

Tests 2 - 6:

Tests 7 - 12:

Tests 13 - 16:

SYMPTOM
P1490 - LOW SPEED 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
- Power distribution center
- Fused B+ circuit open
- Radiator fan ON/OFF relay (coil open)
- Radiator fan ON/OFF relay (internal short to ground)
- Radiator fan ON/OFF relay control circuit shorted to ground
- Radiator fan HIGH/LOW relay (internal short to ground)
- Radiator fan ON/OFF relay control circuit open
- Fused B+ circuit shorted to ground
- Powertrain Control Module
- Low speed radiator fan relay output circuit shorted to ground
- Low speed radiator fan relay output circuit to radiator fan motor shorted to ground
- High speed radiator fan relay output circuit shorted to ground
- Radiator fan motor
- Wiring harness intermittent