What does code P1644 mean?

Q: What does code P1644 mean?

TP Output Circuit. P1644 on GM vehicles indicates that the powertrain control module (PCM) has detected an abnormal condition in the throttle position (TP) output circuit, which is the signal path from the TP sensor to the PCM or from the PCM to other modules. The PCM monitors the voltage on this circuit and sets the code when the signal is out of expected range, stuck, or intermittent, often affecting throttle response and transmission shift feel.

DTC codes / GM codes / P1644

P1644 · GMTP Output Circuit

P1644 on GM vehicles indicates that the powertrain control module (PCM) has detected an abnormal condition in the throttle position (TP) output circuit, which is the signal path from the TP sensor to the PCM or from the PCM to other modules. The PCM monitors the voltage on this circuit and sets the code when the signal is out of expected range, stuck, or intermittent, often affecting throttle response and transmission shift feel.

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.