🔥
P0742 has a very specific symptom: engine stalls when you come to a stop. The torque converter clutch (TCC) is stuck mechanically or hydraulically in the locked position. Coming to a stop, the locked clutch links the engine to the stationary wheels - engine bogs and dies. Most common causes are a stuck TCC solenoid, debris in the valve body, or a failed lockup clutch that's welded itself together internally. See top-rated scanners on Amazon ↑
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0742 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
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🎯 Top Causes & Probability
60%
#1 - Most Likely
Stuck TCC Lockup Solenoid
The TCC solenoid valve has stuck open due to varnish, debris from worn clutches, or an internal failure. Solenoid replacement (often as part of solenoid pack) is the most common fix and runs $300–$900 installed. Common on Ford 6F35, GM 6L80, and Chrysler 62TE.
🔧 Part
$60–$300
👨🔧 Labor
$200–$600
⚡ DIY
Hard
25%
#2 - Check First
Debris in Valve Body
Burnt fluid and clutch material clog the TCC apply/release passages, holding pressure on the clutch. Sometimes a complete fluid exchange and valve body cleaning is enough. Other times the valve body needs to come off for inspection.
🔧 Part
$80–$250
👨🔧 Labor
$300–$800
⚡ DIY
Hard
15%
#3 - Less Common
Failed TCC / Welded Lockup Plate
The lockup clutch friction material has overheated, glazed, or welded to the converter cover. Only fix is a replacement torque converter, which requires trans removal - the most expensive scenario for this code.
🔧 Part
$200–$700
👨🔧 Labor
$800–$1,800
⚡ DIY
Hard
🚗 Most Affected Vehicles
🛈 Is It Safe to Drive with P0742?
Drive carefully if at all - the engine will stall at every stop, which is dangerous in traffic. You can sometimes shift to neutral before stopping to keep the engine running, but that's a workaround, not a fix. Get to a transmission shop the same day. Continued driving with the TCC locked also generates heat in the converter and accelerates further damage. This is not a "drive it for a few weeks" code.
🔧 Step-by-Step Diagnosis
- Confirm the symptom - Engine bogs and stalls when coming to a complete stop in gear - classic TCC stuck-on. Shifting to neutral before stopping prevents the stall = confirmed.
- Read TCC duty cycle live - On a scan tool, watch TCC command and TCC slip. If commanded OFF but slip stays at 0 RPM, the clutch is mechanically stuck.
- Check fluid condition - Burnt fluid often = welded clutch material. Clean fluid with one stuck solenoid = best-case scenario.
- Drop the pan, inspect the TCC solenoid - On many transmissions, you can swap the TCC solenoid alone. Test for free movement of the valve and look for debris.
- Decide: solenoid, valve body, or converter - Clean fluid + sticky solenoid = $400–$900 fix. Burnt fluid + welded clutch = $1,500–$2,500 (converter replacement).
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Use a transmission specialist - this code can have very different price tags
- Ask whether they'll try the solenoid first before condemning the converter
- Request a written estimate covering both scenarios
- Check reviews for recent torque converter / TCC work