What does code P1646 mean?

Q: What does code P1646 mean?

Driver 1 Line 6. P1646 on GM vehicles indicates that the powertrain control module (PCM) has detected a fault on the class 2 serial data line that it uses to communicate with driver 1 devices, specifically line 6 of that network. The PCM monitors the voltage and message traffic on this line and sets the code when the signal is out of range, shorted, or missing entirely for a calibrated period.

DTC codes / GM codes / P1646

P1646 · GMDriver 1 Line 6

P1646 on GM vehicles indicates that the powertrain control module (PCM) has detected a fault on the class 2 serial data line that it uses to communicate with driver 1 devices, specifically line 6 of that network. The PCM monitors the voltage and message traffic on this line and sets the code when the signal is out of range, shorted, or missing entirely for a calibrated period.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyProfessional

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.