What does code P1633 mean?

Q: What does code P1633 mean?

Ignition Power Circuit Low Voltage. P1633 on a GM vehicle means the powertrain control module (PCM) has detected that the ignition power circuit voltage is lower than expected while the engine is running. The PCM monitors this circuit to confirm that the ignition switch and wiring are delivering stable voltage to the control modules, and it sets the code when the voltage drops below a calibrated threshold for a set time.

DTC codes / GM codes / P1633

P1633 · GMIgnition Power Circuit Low Voltage

P1633 on a GM vehicle means the powertrain control module (PCM) has detected that the ignition power circuit voltage is lower than expected while the engine is running. The PCM monitors this circuit to confirm that the ignition switch and wiring are delivering stable voltage to the control modules, and it sets the code when the voltage drops below a calibrated threshold for a set time.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

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