What does code P1491 mean?

Q: What does code P1491 mean?

Radiator Fan Control Relay Circuit Open Or Shorted. P1491 on a GM vehicle means the powertrain control module (PCM) has detected an open or shorted circuit in the radiator fan control relay circuit. The PCM commands the relay on or off and monitors the circuit for expected voltage or continuity, so this code points to a wiring, relay, or connection fault rather than a mechanical cooling problem.

DTC codes / GM codes / P1491

P1491 · GMRadiator Fan Control Relay Circuit Open Or Shorted

P1491 on a GM vehicle means the powertrain control module (PCM) has detected an open or shorted circuit in the radiator fan control relay circuit. The PCM commands the relay on or off and monitors the circuit for expected voltage or continuity, so this code points to a wiring, relay, or connection fault rather than a mechanical cooling problem.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.