4t65e & 4t40/45e - atra · 4t65e & 4t40/45e tcc applying on top of 2nd gear and p0742 ......
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Technical Bulletin # 1186
Copyright © 2008 ATRA. All Rights Reserved. JR> Page 1 of 2
Transmission:Subject:
Application:Issue Date:
4T65E & 4T40/45ETCC Applying on Top of 2nd Gear and P0742GM, BuickJuly, 2008
When encountering this problem, you may be dealing with a faulty TCC release pressure switch. This switch is the only pressure switch located on the Pressure Switch Manifold (PSM) on the late 4T65E and one of six switches on the 4T40/45E and early (97-03) 4T65E Pressure Switch Manifolds. The TCC release switch is a normally closed switch. Anytime lock up is disengaged, the switch will be in the open position and “TCC release” PID on your scanner will display “on” with the release oil against the switch contact. When the TCC release oil is exhausted, (Lock Up) the switch moves to the closed position as the release oil is exhausted and “TCC release” on your scanner will display “off”. It is common for a switch to fail in the closed position and trick the computer into thinking that the release oil is exhausted and that lock up is stuck on. The PCM strategy for this code is to ground the TCC solenoid which results in lock up on top of second gear and freeze the adaptive strategies.
4T65E & 4T40/45ETCC Applying on Top of Second Gear and P0742
Copyright © 2008 ATRA. All Rights Reserved.
Technical Bulletin # 1186
JR > Page 2 of 2
The part that can be confusing is, if the TCC solenoid has mechanically failed, the same code and drivability issue may occur. Use the following diagnostic procedures to accurately separate a bad solenoid or PSM.
1. When the code is set and TCC is engaged in second gear, clear the codes with your scanner. If TCC releases and works again until the code sets, the PSM is faulty.
2. Find the functional test section in your scanner. While driving engage and disengage lock up with the scanner. If TCC responds correctly to the scanner commands, you have tested the entire electrical and mechanical parts of lock up. Replace PSM.
3. Unplug the transmission. Run the engine and put the shifter in drive. If the engine stalls replace the solenoid.
Always check for damage at the pressure switch