P0729
PowertrainTransmissionhigh severityGear 6 Incorrect Ratio
What P0729 Means
The transmission detected that the actual gear ratio in 6th does not match the expected ratio. This usually points to internal slipping or a control fault.
Symptoms
- Slipping in 6th gear
- RPM flare during shifts
- Check engine light on
Common Causes
- Low or worn transmission fluid
- Worn clutches or bands
- Faulty shift solenoid
- Internal transmission wear
Diagnostic Steps
- Scan codes and freeze frame
- Check fluid level and condition
- Monitor gear ratio data during a drive
- Perform pressure test or inspect internals
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Budget handheld~$40
ANCEL AD410 →
No-phone-needed handheld — reads, clears, live data, freeze frame.
✓ ANCEL official store
Serious DIY~$100
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
SHOP FAVORITEShop-grade tablet~$300
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
✓ Autel official store
Pro diagnostics$1,500+
Autel MaxiSys MS906 Pro →
Full-system pro platform — topology mapping, ECU coding, the works.
✓ Autel official store
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