– Dirty transmission fluid
– Faulty pressure control solenoid valve ‘C’
– Pressure control solenoid valve ‘C’ harness is open or shorted
– Pressure control solenoid valve ‘C’ circuit poor electrcial connection
– Shift shock
The Engine Control Module (ECM) uses signals from the vehicle speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th or 5th gear). Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical troubles of the shift solenoid valves and valve body.