Fault codeP0740

MODERATE

Torque Converter Clutch Circuit Malfuction

What this code means

Torque Converter Clutch Circuit Malfuction.

P0740 is a generic code: it means the same thing on every make. P0740 belongs to family P07xx — Transmission. Its page explains how to read a code and groups all its codes by part.

Torque converter lock-up clutch

The torque converter links the engine to an automatic gearbox through fluid. At steady speed, a clutch locks it to avoid slipping and save fuel. The control unit engages it with a solenoid and checks that the engine speed matches the gearbox speed.

What you notice

Engine speed slightly too high at steady speed, higher consumption, shudder as if driving over rumble strips, or the engine stalling when stopping if the clutch stays engaged.

How to check it

Check the fluid level and condition, then the lock-up solenoid's connector and resistance. At steady speed in top gear, Klaro's engine speed should drop by a few hundred rpm when the converter locks.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Engine RPM
Vehicle speed

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
7Transmission
40P0740