What does code P1804 mean?

Q: What does code P1804 mean?

Ground Control Relay. P1804 on GM vehicles indicates that the powertrain control module (PCM) has detected a fault in the ground control relay circuit, which is used to switch the ground path for specific high-current components such as the secondary air injection pump or cooling fan. The PCM monitors the relay control circuit and the resulting voltage or current feedback, and it sets this code when the expected ground path is not established or is lost unexpectedly.

DTC codes / GM codes / P1804

P1804 · GMGround Control Relay

P1804 on GM vehicles indicates that the powertrain control module (PCM) has detected a fault in the ground control relay circuit, which is used to switch the ground path for specific high-current components such as the secondary air injection pump or cooling fan. The PCM monitors the relay control circuit and the resulting voltage or current feedback, and it sets this code when the expected ground path is not established or is lost unexpectedly.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

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