OBD-II trouble code
P0742: Torque Converter Clutch Circuit Stuck On
The torque converter clutch is staying locked when it should release. The classic giveaway is the engine stalling as you come to a stop — like a manual-transmission car you forgot to declutch — because the engine and transmission can't decouple at idle.
Quick facts
- System
- Powertrain
- Category
- Transmission / Torque Converter
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $150 – $1,200
- DIY difficulty
- Shop recommended
What does P0742 mean?
P0742 is the opposite of P0741. P0741 means the torque converter clutch won't lock up; P0742 means it won't let go. The lockup clutch inside the converter is supposed to mechanically couple the engine to the transmission only when you're cruising, then release before you slow to a stop so the engine can idle independently of the drivetrain. When that clutch stays applied — stuck on — the engine stays mechanically tied to the wheels even as you brake to a halt, and the result is the signature P0742 symptom: the engine stalls when you come to a stop, exactly the way a manual car stalls if you brake without pushing the clutch in.
Mechanically, a stuck-on TCC usually traces to the hydraulic side rather than the electrical side. The most common cause is a TCC solenoid or valve that's stuck in the applied position — varnish buildup, debris, or wear holding the apply circuit open so pressure keeps reaching the clutch. A stuck valve body valve, internal cross-leak, or a solenoid that's failed in the energized state will do the same thing. Old or contaminated transmission fluid is a frequent contributor because the varnish that gums up these valves comes from neglected fluid. Less often, an electrical fault commands the solenoid on continuously.
Beyond the stalling at stops, drivers may notice a shudder or lugging feeling at low speed (the engine being dragged down because it can't slip the converter), harsh behavior when slowing, and sometimes a no-idle-in-gear condition. The transmission usually still shifts through its gears — like the other TCC codes, the fault is specific to lockup behavior. Because the stalling can happen at intersections, P0742 is worth addressing promptly even though the car is technically drivable. A transmission fluid service is the right first move on many of these since fresh fluid can free a varnished valve, but a solenoid or valve-body fault that won't clear with fluid is common enough that the diagnosis shouldn't stop there.
Common causes
- TCC solenoid stuck in the applied (energized) position
- Stuck TCC apply valve in the valve body from varnish or debris
- Old, contaminated transmission fluid causing valve stiction
- Internal valve-body cross-leak keeping pressure on the clutch
- Worn valve body allowing the apply circuit to stay pressurized
- Electrical fault commanding the solenoid on continuously (less common)
- Debris from transmission wear lodged in the TCC circuit
- Recent service with incorrect fluid affecting valve operation
Symptoms
- Engine stalls when coming to a stop (the signature symptom)
- Check engine light on with P0742 stored
- Shudder or lugging feeling at low speed
- Harsh or jerky behavior when decelerating
- Engine RPM tied unnaturally to road speed at low speed
- Stalling when shifting into gear or at idle in gear
- Transmission otherwise shifts through all gears
Diagnostic steps
- 1.Confirm the symptom pattern: stalling specifically as the vehicle comes to a stop strongly indicates a TCC that won't release.
- 2.Read live data and watch TCC commanded vs. actual status at low speed — a clutch that stays applied when commanded off confirms stuck-on behavior.
- 3.Check transmission fluid level and condition first. Varnished fluid is a leading cause and a fluid service can free a sticking valve.
- 4.Inspect the TCC solenoid connector and verify the PCM is actually commanding the solenoid off when it should.
- 5.Resistance-check the TCC solenoid against spec to rule out an electrical failure holding it on.
- 6.If fluid and electrical check out, the apply valve or valve body is the suspect — a valve-body service or replacement is the next step.
Repair cost
$150 – $1,200
A transmission fluid service runs $150-$300 and can free a varnished valve in a meaningful share of P0742 cases — it's the right first try. TCC solenoid replacement is $250-$700 depending on pan/valve-body access. A stuck valve in the valve body can require a valve-body service or replacement, pushing the cost toward $600-$1,200. Because the stalling happens at stops, prioritize the diagnosis even though the car still drives.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with transmission shift solenoid replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.