P0725: Engine speed input to gearbox: circuit fault

What P0725 means

The automatic gearbox control unit needs to know engine speed to decide when to shift and to check nothing is slipping. Depending on the car, that signal arrives by a wire from the crankshaft sensor or over the network linking the control units. This code means the signal is missing or not valid.

Most common causes

• Other crankshaft sensor codes that explain the fault
• Loose or corroded crankshaft sensor connector
• Damaged wiring between the engine and the gearbox control unit
• Communication fault between control units
• Faulty crankshaft sensor
• Gearbox or engine control unit fault (uncommon)

Symptoms

• Harsh shifts or limp mode
• Rev counter failing or dropping to zero
• Jerking or stalling if the fault lies with the crankshaft sensor
• Engine or gearbox warning light on

Can you drive with P0725?

With care You can drive with care, but if the crankshaft sensor is the cause the engine may cut out or refuse to start. Have it checked as soon as possible.

How to check it

Look for crankshaft sensor codes or network codes (those starting with U) stored at the same time: if there are any, the problem usually lies there rather than in the gearbox. Also watch whether the rev counter moves normally.

How to read and clear P0725 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 P0725 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

• P0717 Input/turbine speed sensor: no signal
• P0720 Output speed sensor: circuit fault
• P0721 Output speed sensor: range/performance
• P0722 Output speed sensor: no signal
• P0729 Incorrect gear ratio in sixth gear
• P0730 Incorrect gear ratio in the automatic gearbox
• P0731 Incorrect gear ratio in first gear
• P0732 Incorrect gear ratio in second gear
• P0700 Transmission control system: fault detected
• P0701 Transmission control system: range/performance
• P0702 Transmission control system: electrical fault
• P0703 Torque converter/brake switch B: circuit fault

P0725 is a generic code, so it means the same on any make, for example on Abarth, Alfa Romeo, Cupra, Jeep, Nissan, Škoda. See what Final OBD does on your car in makes and models.