P0730: Incorrect Gear Ratio
Can you still drive? Not recommended. The transmission is slipping or not engaging gears properly. Continued driving can cause complete transmission failure and significantly increase repair costs.
What Does P0730 Mean?
Code P0730 indicates the TCM has detected that the actual gear ratio does not match the expected gear ratio for the commanded gear. The TCM calculates gear ratio by comparing the input and output speed sensors. This code often points to internal transmission wear, slipping clutch packs, or a failing torque converter, though it can also be caused by speed sensor issues.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Worn transmission clutch packs
- Failing torque converter
- Low or burnt transmission fluid
- Faulty input or output speed sensor
- Worn transmission bands
Symptoms
- Check engine light on
- Transmission slipping noticeably
- Delayed or flared shifts
- RPM climbs without corresponding speed increase
- Shuddering during acceleration
Diagnostic Steps
- 1Read freeze frame data noting input RPM, output RPM, and commanded gear
- 2Check transmission fluid level and condition for burnt smell or discoloration
- 3Verify input and output speed sensors are reading correctly
- 4Perform stall speed test to check torque converter
- 5Monitor gear ratio calculations in each gear with scan tool
- 6If all sensors are good, internal transmission inspection is needed
Recommended Parts & Tools
transmission fluid
transmission filter kit
OBD-II scan tool with TCM access
torque converter
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $200 - $4500 |
| Parts Only (DIY) | $80 - $200 |
| Labor (1-2 hrs @ $100/hr) | $100 - $200 |
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Chat with AI About P0730Commonly Affected Vehicles
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Frequently Asked Questions
Does P0730 mean I need a new transmission?
Not necessarily, but it is a serious code. If the cause is internal wear or burnt clutch packs, a rebuild or replacement may be needed. If it is a sensor or fluid issue, the repair is much less expensive.
Can low transmission fluid cause P0730?
Yes. Low fluid causes inadequate clutch pack clamping pressure, which leads to slipping and incorrect gear ratios. Check the fluid level and condition immediately.
What does incorrect gear ratio mean?
It means the transmission is not achieving the expected mechanical ratio between engine speed and output shaft speed. For example, in 3rd gear the ratio should be fixed, but the TCM detects the ratio is off, indicating slippage.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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