EngineLightCodes
Powertrain code

P0742 Torque Converter Clutch Circuit Stuck On

Severity
Fix soon
Typical repair cost
$220–$3,300
Do it yourself
Shop job
Shop time
1.5–10 hours

P0742 means the converter clutch stays applied although commanded off – there is almost no slip.

How the engine computer detects it

GM's T43 flags −50 to +13 rpm for 1.5 s six times and the 6T70 −20 to +30 rpm for 2.5 s, both after one trip; Allison and Saab's Aisin AF40 after two trips, the AF40 also when the engine stalls without slip. Typical is the engine stalling when stopping or when selecting D or R, plus jerking at low speed. Note the different uses: Ford's P0742 is a short to ground in the clutch solenoid circuit (stuck on is P2758 there), and Saab's 9-3 of 2003 uses it for a mechanical lock-up fault.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • Engine stalls when stopping or selecting D/R
  • Jerking or bucking at low speed
  • Check engine light or transmission warning

Common causes

  1. Converter clutch control valve sticking in the applied position Most likely
  2. Solenoid stuck open (or short to ground with low-side control) Possible
  3. Lock-up clutch seized in the converter Possible
  4. Wrong fluid level or contaminated fluid Possible
  5. Engine or turbine speed signal implausible Less likely

How to diagnose P0742

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: torque converter clutch solenoid, torque converter, transmission valve body, transmission control module.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
7
Transmission
42
Specific fault

Questions drivers ask

Can I drive with code P0742?

If the car shifts normally, drive gently to a shop. If it's stuck in one gear, slips, shifts harshly or won't move out of Park, don't drive it: have it towed.

Will my car pass an emissions inspection with P0742?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.