Possible causes – Poor connection at the AC motor control module – Open or short circuit condition – Failed AC Motor Control Module When is the code detected? No duty signals are input from the MCM for at least 5
Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1644 Information for specific makes P1644 BUICKP1644 CADILLACP1644 CHEVROLETP1644 FORDP1644 GMCP1644 HONDA
P1644 GMC – Traction Control Delivered Torque Output Circuit
P1644 BUICK – TP Output Circuit
P1644 CADILLAC – TP Output Circuit
P1644 CHEVROLET – Traction Control Delivered Torque Output Circuit
P1644 FORD – Fuel Pump Speed Control Circuit Malfunction