What does code P1518 mean?

Q: What does code P1518 mean?

Throttle Actuator Control (TAC) Module Serial Data Circuit. P1518 on a GM vehicle means the engine control module (ECM) has lost or corrupted the serial data communication link with the throttle actuator control (TAC) module, which is the separate controller that operates the electronic throttle body. The ECM expects a continuous, coded message from the TAC module and sets this code when that message is missing, intermittent, or fails its internal checksum.

DTC codes / GM codes / P1518

P1518 · GMThrottle Actuator Control (TAC) Module Serial Data Circuit

P1518 on a GM vehicle means the engine control module (ECM) has lost or corrupted the serial data communication link with the throttle actuator control (TAC) module, which is the separate controller that operates the electronic throttle body. The ECM expects a continuous, coded message from the TAC module and sets this code when that message is missing, intermittent, or fails its internal checksum.

SystemPowertrain

Code typeGM specific

SeverityHigh

Fix difficultyProfessional

AreaVehicle speed, idle control and auxiliary inputs

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