P0730 means Incorrect Gear Ratio. Comparing input and output speeds, the computer sees a gear ratio that does not match the gear it commanded, which usually means slipping. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0730 means
Electronically controlled automatics are run by a transmission control module (TCM), a separate box or part of the engine computer. It reads speed sensors, the range sensor and fluid temperature to decide when to shift, and drives solenoids that apply clutches and the torque converter clutch. Many basic code readers only show the generic P0700; a scan tool that reads the transmission module shows the specific fault. Check fluid level and condition first, since low or burnt fluid causes many transmission codes.
P0730 symptoms
- Engine speed flaring between gears
- Slipping or delayed engagement
- Limp mode
Common causes of P0730
- Low or burnt fluid
- Worn clutches or bands
- Shift solenoid or valve body problems
- Internal hydraulic leaks
How to diagnose P0730
- Check fluid level and condition first
- Look for gear-specific ratio codes (P0731 to P0736) that show which gear slips
- Check solenoid operation and line pressure
Can you drive with P0730?
Limit driving: slipping creates heat and debris that make the damage worse.
P0730 tips
The gear-specific codes P0731 to P0736 narrow the problem to one gear, which helps separate a solenoid fault from worn clutches. Dark, burnt-smelling fluid with friction material in the pan points to internal wear rather than an electrical fault.
Will P0730 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0730 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0715 | Input/Turbine Speed Sensor A Circuit |
| P0700 | Transmission Control System Malfunction |
| P0750 | Shift Solenoid A Malfunction |
| P0741 | Torque Converter Clutch Circuit Performance or Stuck Off |
Guides that help
- transmission shifting hard
- delayed engagement
- transmission slipping
- transmission fluid color
- transmission rebuild vs replacement
When it is more than a sensor
If the fault turns out to be internal (worn clutches, a failed converter or a damaged valve body), compare a rebuild with a replacement in transmission rebuild vs replacement and transmission replacement cost, identify your unit with what transmission do I have?, and browse our transmissions.
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