P2758: Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck On
Do not keep driving
Expect the engine to stall when you come to a stop — the converter clutch is stuck applied, which is like being in gear with no clutch pedal. Drive it as little as possible and have it recovered if it stalls in traffic. Check the transmission fluid; degraded fluid is a common cause.
What this code means
The torque converter clutch pressure control solenoid is holding the clutch applied.
The torque converter clutch is what stops an automatic wasting fuel at cruise, and it has to be applied gradually rather than switched on.
A torque converter drives through fluid, which always slips a little — that is what makes an automatic smooth from rest, and it is a permanent efficiency loss once moving. So above a certain speed the converter is locked mechanically, bolting engine to gearbox and removing the slip.
Locking it abruptly would feel like a gear change nobody asked for, so the clutch is applied through a pressure control solenoid that ramps it, and often holds it in controlled slip — deliberately allowing a few tens of revolutions per minute of difference to absorb engine pulses. That is what this solenoid regulates.
Stuck applied is the one you will feel. A converter clutch that cannot release is a manual gearbox with no clutch pedal — the engine stalls when you come to a stop, exactly as it would if you braked in gear without dipping the clutch. Expect stalling at junctions and heavy shuddering at low speed.
The shudder worth knowing about: a converter clutch slipping when it should be locked produces a rhythmic vibration at light throttle, most often between about 60 and 80 km/h, which drivers describe as rumble strips or a rough road. It is frequently mistaken for tyres, wheel balance or driveline vibration, and the distinguishing test is that it appears only under gentle acceleration at steady speed and disappears the moment the throttle is lifted or pressed harder.
Fluid condition matters here more than almost anywhere else. Controlled slip depends on the fluid's friction modifiers, which degrade with heat and age — so shudder is very often old fluid rather than a failed part, and a fluid service is the cheap first move.
Transmission fluid is the first thing to check and the thing most often skipped.
It is not a lubricant that also happens to move things — it is the working fluid of a hydraulic machine. It carries the pressure that applies every clutch, it carries the heat away, it lubricates, and it is the friction surface itself: the additive package is tuned so clutches grip smoothly rather than snatching.
So fluid that is low, old, burnt or of the wrong specification changes how the transmission behaves, and it does so before any part has failed. Burnt fluid smells burnt and looks dark; healthy fluid is translucent. Checking it costs nothing and rules out a great deal.
"Filled for life" is a claim about the warranty, not the transmission. Many sealed units have no dipstick and a manufacturer schedule that never changes the fluid, and they still wear out faster on original fluid than on serviced fluid.
Likely causes
Start here
- Faulty torque converter clutch solenoid · specialist
- Low or degraded transmission fluid · moderate
- Debris in the transmission fluid · specialist
- Corroded or loose connector · specialist
Less common
- Worn torque converter clutch · specialist
Rare
- Faulty transmission control module · specialist
Symptoms
Components involved
Information, not instruction
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