What does code P1665 mean?

Q: What does code P1665 mean?

Driver 3 Line 5. P1665 on GM vehicles indicates that the powertrain control module (PCM) has detected a fault on the serial data line it uses to communicate with driver 3, specifically on line 5 of that driver circuit. This is a manufacturer-specific communication code, not a generic OBD-II emissions fault, and it typically points to an open, short, or excessive resistance on that dedicated control circuit.

DTC codes / GM codes / P1665

P1665 · GMDriver 3 Line 5

P1665 on GM vehicles indicates that the powertrain control module (PCM) has detected a fault on the serial data line it uses to communicate with driver 3, specifically on line 5 of that driver circuit. This is a manufacturer-specific communication code, not a generic OBD-II emissions fault, and it typically points to an open, short, or excessive resistance on that dedicated control circuit.

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.