Low transmission fluid level
Dirty transmission fluid
Faulty shifting solenoid valve
Shifting solenoid valve harness is open or shorted
Shifting solenoid valve circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
Transmission shift shock
The Transmission Control Module (TCM) monitors the transmission mechanical shifting through various sensors. This malfunction is detected when the A/T does not shift as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking,improper solenoid valve operation, etc.