Low or degraded transmission fluid; Worn clutches or bands; Faulty shift solenoid or valve body; Low line pressure; Faulty speed sensor.

P0730: Incorrect Gear Ratio

Q: What does P0730 mean?

P0730: Incorrect Gear Ratio. The transmission control module compares input and output shaft speeds. This code means the measured ratio does not match any expected gear, which usually indicates slipping.

Q: Is it safe to drive with P0730?

Severity: High. Limit driving and diagnose promptly. Continued driving can cause damage, stalling or limp mode.

P0730 means Incorrect Gear Ratio. The transmission control module compares input and output shaft speeds. This code means the measured ratio does not match any expected gear, which usually indicates slipping.

CodeP0730

SystemTransmission

SeverityHigh

TypeGeneric powertrain

Can I keep driving? Limit driving and diagnose promptly. Continued driving can cause damage, stalling or limp mode.

Common symptoms

Check engine light on
Slipping (RPM flares without acceleration)
Delayed engagement or harsh shifts
Limp mode

Possible causes

Low or degraded transmission fluid
Worn clutches or bands
Faulty shift solenoid or valve body
Low line pressure
Faulty speed sensor

How to diagnose P0730

Check fluid level and condition (burnt smell, debris).
Check for solenoid or speed sensor codes.
Check line pressure.
Internal repair may be needed if fluid and electrical checks are fine.

What the code means, digit by digit

PPowertrain0Generic (SAE) code7Sub-system30Specific fault

Generic codes have the same definition on every OBD-II vehicle (petrol cars from model year 1996 in the US, 2001 in the EU; diesels later). Manufacturers can add their own enhanced codes; those are not listed here.

Symptoms linked to P0730

Transmission slipping

Related codes

General guidance only. Fault codes describe what the engine computer saw, not which part failed: confirm with testing before replacing parts, and follow the vehicle's service information.