Possible causes

– Low transmission fluid level
– Dirty transmission fluid
– Faulty torque converter clutch solenoid valve
– Torque converter clutch solenoid valve harness or connectors
– Torque converter clutch solenoid valve circuit is open or shorted
– Transmission internal mechanical problem

Tech notes

When the a transmission solenoid is stuck on, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is very dirty, it is recommend changing the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a transmission mechanical failure and that the transmission will need to be rebuilt or replaced.

When is the code detected?

The Transmission Control Module (TCM) has detected slippage on the Torque Converter Clutch (TCC) during a period when the converter is commanded off

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0742 Description

The Torque Converter Clutch (TCC) solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Lock-up piston operation will then be controlled. When the torque converter clutch solenoid valve is activated, the torque converter lockup clutch will engage creating a 1 to 1 RPM ratio between the transmission input shaft and the rotational speed of the torque converter.
Lock-up operation, however, is prohibited when A/T fluid temperature is too low.
When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.

P0742 Information for specific makes

P0742 ACURA
P0742 BMW
P0742 CHEVROLET
P0742 CHRYSLER
P0742 DODGE
P0742 GMC
P0742 HYUNDAI
P0742 ISUZU
P0742 JEEP
P0742 KIA
P0742 MAZDA
P0742 MITSUBISHI
P0742 SUZUKI
P0742 BUICK
P0742 CADILLAC
P0742 PONTIAC
P0742 SATURN