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P0740: Torque converter clutch circuit fault

There is a fault in the control of the clutch that locks the torque converter in the automatic gearbox, often fluid, wiring or the solenoid.

Code P0740 at a glance
CodeP0740
SystemEngine and transmission
GroupP07xx, Transmission
TypeGeneric: it means the same on every make
Can you keep driving?With care

What P0740 means

The torque converter links the engine to the automatic gearbox. At a steady speed an internal clutch locks it so no power or fuel is wasted, and that clutch is worked by a solenoid controlled by the ECU. The control unit has found a fault with the torque converter clutch solenoid or its circuit, without saying whether it is electrical or mechanical.

Most common causes

  • Low or badly worn gearbox fluid
  • Connector for the torque converter clutch solenoid loose, corroded or with fluid inside
  • Damaged wiring between the control unit and the gearbox
  • The torque converter clutch solenoid failed or jammed with dirt
  • Dirty or worn valve body
  • Transmission control unit (uncommon)

Symptoms

  • Engine warning light on
  • Higher revs and fuel use at a steady speed
  • Judder at low speed or when stopping
  • On some cars the gearbox goes into limp mode

Can you drive with P0740?

With care You can keep driving gently, but get it looked at soon: the gearbox fluid runs hotter and the torque converter can end up damaged.

How to check it

First check the gearbox fluid level and colour if there is a dipstick, and look at the gearbox connector for looseness or fluid inside. Note which gear and what temperature the fault appears at so you can tell the garage.

How to read and clear P0740 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0740 with this same explanation and whether it’s confirmed, pending or permanent.

This code is usually stored by the gearbox control unit. With Free you read it for nothing with its short description, because Free reads every control unit; with Pro you also get the full explanation, how the car was running when it was logged and clearing.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P0740 is a generic code, so it means the same on any make, for example on BMW, Ford, Mercedes-Benz, Peugeot, Renault, Volkswagen. See what Final OBD does on your car in makes and models.

What does code P0740 mean?

The torque converter links the engine to the automatic gearbox. At a steady speed an internal clutch locks it so no power or fuel is wasted, and that clutch is worked by a solenoid controlled by the ECU. The control unit has found a fault with the torque converter clutch solenoid or its circuit, without saying whether it is electrical or mechanical.

Can you drive with P0740?

You can keep driving gently, but get it looked at soon: the gearbox fluid runs hotter and the torque converter can end up damaged.

How do you clear P0740?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0740 comes back.