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P0730: Incorrect gear ratio in the automatic gearbox

The automatic gearbox sees that input and output speeds don’t match the selected gear. Low or worn fluid and internal wear are typical.

Code P0730 at a glance
CodeP0730
SystemEngine and transmission
GroupP07xx, Transmission
TypeGeneric: it means the same on every make
Can you keep driving?With care

What P0730 means

The transmission control unit compares how fast the shaft going into the gearbox turns with the shaft coming out. Every gear has a fixed ratio; this code means one of them isn’t being met, without saying which. It points to the automatic gearbox, not the engine.

Most common causes

  • Low gearbox fluid, often from a leak at the sump or seals
  • Old, burnt or incorrect type of gearbox fluid
  • Input or output speed sensor, or its connector, giving false readings
  • Dirty or faulty solenoids or valve body (the block that routes the fluid)
  • Worn clutches or bands inside the gearbox

Symptoms

  • Engine warning light on
  • Revs rise but the car doesn’t pick up speed
  • Harsh, late or missed gear changes
  • Gearbox stays in one gear (limp mode)

Can you drive with P0730?

With care You can drive gently to a garage, but a slipping gearbox wears quickly and the repair gets more expensive. Avoid hard acceleration, steep hills and towing.

How to check it

If the gearbox has a dipstick, check the fluid level and condition with the engine warm: dark or burnt-smelling fluid is a bad sign. With a scanner, live input and output shaft speeds help the garage see which gear is slipping.

How to read and clear P0730 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 P0730 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

P0730 is a generic code, so it means the same on any make, for example on Abarth, Cupra, Jeep, Mini, Nissan, Seat. See what Final OBD does on your car in makes and models.

What does code P0730 mean?

The transmission control unit compares how fast the shaft going into the gearbox turns with the shaft coming out. Every gear has a fixed ratio; this code means one of them isn’t being met, without saying which. It points to the automatic gearbox, not the engine.

Can you drive with P0730?

You can drive gently to a garage, but a slipping gearbox wears quickly and the repair gets more expensive. Avoid hard acceleration, steep hills and towing.

How do you clear P0730?

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, P0730 comes back.