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TransmissionSeverity High: diagnose before driving on

P0731Gear 1 Incorrect Ratio

What it means

In first gear the ratio between input and output shaft speeds is not what it should be. The transmission is slipping, or one of the speed signals is wrong.

Symptoms

  • Engine revs rise without the car speeding up (slipping)
  • Harsh or delayed shifts
  • Limp mode

Common causes

  • Low or burnt transmission fluid
  • Worn clutch packs or bands
  • Faulty input or output speed sensor
  • Internal hydraulic leak or valve body fault

What to check first

  1. Check fluid level and condition
  2. Compare input, output and engine speed in live data
  3. Look for metal or friction material in the pan
Can I drive with P0731? Not recommended. P0731 can lead to stalling, limp mode or engine damage; diagnose it before driving further.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P0731: questions and answers

What does P0731 mean?

P0731: Gear 1 Incorrect Ratio. In first gear the ratio between input and output shaft speeds is not what it should be. The transmission is slipping, or one of the speed signals is wrong.

What are the symptoms of P0731?

Engine revs rise without the car speeding up (slipping). Harsh or delayed shifts. Limp mode.

What causes P0731?

Low or burnt transmission fluid. Worn clutch packs or bands. Faulty input or output speed sensor. Internal hydraulic leak or valve body fault.

How do you diagnose P0731?

1. Check fluid level and condition 2. Compare input, output and engine speed in live data 3. Look for metal or friction material in the pan

Can I drive with P0731?

Not recommended. P0731 can lead to stalling, limp mode or engine damage; diagnose it before driving further.