What does code P1684 mean?

Q: What does code P1684 mean?

Driver 5 Line 4. P1684 on a GM vehicle indicates that the powertrain control module (PCM) has detected a fault on the Class 2 serial data bus circuit assigned to Driver 5 Line 4, which is a communication line used by the PCM to exchange data with other modules. The PCM monitors the voltage and message traffic on this line and sets the code when the signal is out of range, missing, or shorted, preventing reliable data transfer.

DTC codes / GM codes / P1684

P1684 · GMDriver 5 Line 4

P1684 on a GM vehicle indicates that the powertrain control module (PCM) has detected a fault on the Class 2 serial data bus circuit assigned to Driver 5 Line 4, which is a communication line used by the PCM to exchange data with other modules. The PCM monitors the voltage and message traffic on this line and sets the code when the signal is out of range, missing, or shorted, preventing reliable data transfer.

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.