P0742 code: Torque Converter Clutch Circuit Stuck On
P0742 means torque Converter Clutch Circuit Stuck On. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0742 means
P0742 means the torque converter clutch is staying applied when it should release — the opposite problem of the stuck-off codes. The converter's job at low speed is to slip like a fluid coupling so the engine can idle while the car is stopped in gear; a locked clutch removes that slip, so as you brake to a stop the engine gets dragged down and can stall — exactly like a manual-transmission car left in gear at a red light. That stalling-at-stops behavior is the signature symptom, and it's a genuine safety concern in traffic. Causes are usually hydraulic: a TCC solenoid stuck on, a lockup valve jammed by debris or varnish in the valve body, or contaminated fluid — which is why fluid condition is the first check. Wiring shorts that hold the solenoid energized are possible but less common.
P0742 symptoms
- Engine stalls or nearly stalls when coming to a stop
- Engine lugs or shudders at low speed, like a manual left in gear
- Harsh bump when shifting into gear from a stop
- RPM feels chained to road speed even at low speeds
- Check-engine light
What it costs to fix P0742
Varies by vehicle — get it diagnosed.
The repair cost for this code depends too much on your exact vehicle and the underlying cause to quote a meaningful range. Confirm the cause first so you only pay for the fix you actually need.
Diagnose P0742 for my vehicle →How to fix P0742
Moderate — doable at home with common tools and patience
- Confirm the signature symptom
Note whether the engine gets dragged down, shudders, or stalls as you brake to a stop — that's a converter clutch staying locked when it should release, exactly like stopping a manual car without pushing the clutch in. Confirming this behavior matters because stalling in traffic makes this code a fix-now item, not a someday item.
- Inspect the fluid for contamination
Check color and smell: varnish and debris in old fluid are what jam the lockup valve in the applied position, making fluid condition the number-one suspect for a stuck-ON clutch. Clean, fresh fluid shifts suspicion toward the solenoid or a wiring short instead.
- Service the fluid and filter
If the fluid is degraded, a fluid and filter change can flush the varnish holding the valve and is the cheapest realistic cure. Drive it afterward through several full warm-up cycles before judging — sticky valves sometimes free up gradually.
- Test the solenoid circuit for a stuck-on condition
Check the TCC solenoid's resistance and verify the wiring isn't shorted in a way that holds the solenoid energized — a short here applies the clutch electrically no matter what the computer wants. A scan tool that shows commanded versus actual TCC state separates an electrical fault from a hydraulic one.
- Clean or repair the valve body lockup circuit
If fresh fluid and a good solenoid don't release the clutch, the lockup valve itself is stuck with wear or debris in the valve body. That's a valve-body removal, cleaning, or replacement — the point where this becomes a bench job.
DIY or shop? Symptom confirmation, the fluid check, and a fluid-and-filter service are all home-mechanic work, and electrical testing of the solenoid circuit is manageable with a multimeter and patience. Valve-body work is where most people should hand it over — it demands cleanliness, careful reassembly, and torque discipline that reward shop experience. Until it's fixed, treat the car gently: a transmission that stalls the engine at stops is a genuine traffic-safety problem, not just an annoyance.
Tools for the DIY steps: OBD2 scanner with transmission data · Transmission fluid and filter kit · Drain pan and funnel · Multimeter · Socket set and torque wrench
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0742.
Start a case with P0742 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0742?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0742: common questions
Why does my car stall when I stop?
With the converter clutch stuck on, the engine is rigidly coupled to the wheels — so when the wheels stop, the engine is forced down with them, exactly like stopping a manual car without pressing the clutch. It's the defining P0742 symptom and the reason not to ignore this code.
Is stalling at stops dangerous?
It can be. A stall while braking costs you power steering and vacuum brake assist within moments, potentially in the middle of traffic. Treat active stalling as a park-it problem: stop driving and have it towed for diagnosis.
Could dirty fluid cause P0742?
Very plausibly. Varnish and debris are exactly what jam a lockup valve in the applied position, and a fluid and filter service is the cheapest first strike. If the valve or solenoid is mechanically worn rather than just gummed, cleaning helps only temporarily and the part needs replacing.
How is P0742 different from P0741?
They're opposites: P0741 means the clutch won't apply properly (stuck off/slipping) — costing fuel economy and adding heat. P0742 means it won't release (stuck on) — which can stall the engine at stops. Stuck-on is the more immediately disruptive of the two, even though both share the same solenoid and valve hardware.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0742 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0742 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.