DTC 39

Code 39. 1991 Models:

Circuit Description:
The purpose of the Torque Converter Clutch (TCC) feature is to eliminate the power loss of the torque converter stage when the vehicle is in a cruise condition. This allows the convenience of the automatic transmission and the fuel economy of a manual transmission.

Fused battery ignition voltage is supplied to the TCC solenoid which is used inside the valve body to shift a spool valve to modulate pressure to the Torque Converter Clutch (TCC). This modulated pressure normally allows some slight slippage of the TCC.
The PCM/TCM will engage the TCC by grounding CKT 422 to energize the solenoid.

Code 39 will set if:
^ TCC is engaged.
^ TCC "slip" is greater than 65 rpm for 2 seconds.
^ 2nd or 3rd gear is selected or indicated.

Code 39. 1991 Models:

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test will determine if transmission is receiving a TCC command to the pass-thru connector.

2. Checks for power to transmission.

3. Determines if PCM/TCM is commanding TCC "ON."


Diagnostic Aids:
Clear codes and recheck for Code 39. If code resets, problem could be internal to the transmission.

Code 39 will only set in 3rd gear. TCC slip in 4th gear will set Code 68.