P0742 on Pontiac: How to Diagnose & Fix
Torque Converter Clutch Circuit Stuck On
1 Pontiac model · 1 documented issue · 1 critical
P0742 on Pontiac by model: symptoms, diagnosis and fix
The 4T65-E in 2001-2008 Grand Prix models has several different shift and failure conditions, not one single cause. Examples include P0756/P0757 shift faults, P0741/P0742 TCC paths, pressure-control and valve-body work, second-clutch shudder, V8 torque-converter conditions, slips/no drive/reverse and code-specific valve-body reconditioning (including 10025065 for 2001-2008). A single accumulator, clutch-pack, solenoid or pan-magnet explanation does not fit them all; the cause depends on the unit/RPO and calibration and on whether the fault is hydraulic, electrical or mechanical.
Common Symptoms
- Transmission slips
- Hard or harsh shifting
- No overdrive
- Check engine light with shift or torque-converter clutch codes
How to Fix
Identify the transmission by VIN/RPO and capture codes, freeze-frame, commanded/actual gear, shift timing and temperature. Inspect fluid/debris, cooler flow and line pressure, then follow the code- and unit-specific tree before solenoid, valve-body, converter, clutch or unit replacement. Confirm the unit/RPO, the failed component, calibration, part number and VIN fitment before buying a solenoid, valve body, clutch kit, accumulator, magnet or transmission.
Sources for this issue (3)
P0742 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0742 mean on a Pontiac?
P0742 stands for "Torque Converter Clutch Circuit Stuck On." P0742 means the torque converter clutch (TCC) circuit is stuck on, meaning the lockup clutch that mechanically links the engine to the transmission stays engaged when it should release. The computer commands the clutch on and off, and when it detects the converter clutch remaining applied, it sets this code. The classic symptom is the engine stalling when coming to a stop, similar to driving a manual without pushing the clutch in, along with possible harsh shifts or poor fuel economy. It points to a hydraulic or solenoid problem inside the transmission rather than the engine. On Pontiac it is documented across 1 model: Grand Prix.
What are the most common causes of P0742?
The most common causes of P0742 are: Stuck or failed torque converter clutch solenoid, Stuck valve in the valve body (TCC apply valve), Contaminated or degraded transmission fluid, Internal transmission hydraulic leak holding the clutch on, Wiring or connector fault to the TCC solenoid, Faulty torque converter, Dirty or clogged transmission filter. The specific cause varies by vehicle.
How much does it cost to fix P0742 on a Pontiac?
Repair costs vary widely with the root cause and Pontiac model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.