What P0730 means
Incorrect Gear Ratio
How to diagnose
- Read freeze frame data. When P0730 set, your ECU snapshotted every sensor at that moment. This tells you what the car was doing when the fault triggered — RPM, load, coolant temp, throttle position, fuel trims. Almost always enough info to figure out the cause without further testing.
- Check for related codes. If you have P0730 plus other codes, fix the earliest one in the chain first — a single root cause often triggers multiple codes.
- Cheap fixes first. For most codes, the order is: inspect connectors + wiring (free), check for vacuum leaks (cheap), replace sensor (moderate), replace mechanical part (expensive). Follow that ladder before dropping money on parts.
Manufacturer-specific descriptions
Different manufacturers use P0730 for slightly different failure modes:
| AUDI | Defective Shift Solenoids, Defective Engine Coolant Temperature Sensor, Defective Valve Body, Dirty transmission fluid that restricts the hydraulic passages |
| BMW | Incorrect Gear Ratio |
| FORD | Incorrect Gear Ratio |
| HONDA | Problem in Shift Control System |
| MITSUBISHI | Incorrect Gear Ratio |
| NISSAN | Incorrect Gear Ratio |
| VOLKSWAGEN | Incorrect Gear Ratio |
Read P0730 on your own car
DIY Fix My Car reads P0730 plus 25,000+ other DTC codes with manufacturer-specific descriptions. Includes freeze frame data, likely fix parts, and AI mechanic chat. Download free.