DTC P0730
DTC P0730: Incorrect Gear Ratio
General Description
The transmission control module (TCM) monitors actual gear ratio (the ratio of input speed and output speed of the transmission) while shift changing and driving at a fixed gear. If the TCM detects unexpected actual gear ratio due to clutch slip, abnormal hydraulic pressure, and/or mechanically abnormal in the transmission, the TCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 1 second or more |
| DTC Type | One drive cycle, MIL on*, A/T gear position indicator blinks |
*: MIL comes on at second drive cycle
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| ATF temperature [ATF Temperature] | -40 °F (-40 °C) | - |
| Shift position/mode | D, R | |
| Other | Engine speed [Engine Speed] is more than 400 rpm or transmission output speed [Transmission Output Speed] is more than 2, 500 rpm | |
[ ]: HDS Parameter
Malfunction Threshold
One of these conditions is met:
- The actual gear ratio while the vehicle is stopped or driven in each gear is higher or lower than expected.
- The actual gear ratio when downshift associated with switching of dog clutch is higher or lower than expected.
Possible Cause
The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- Transmission internal failure
Confirmation Procedure
Operating Condition
- 1.
Start the engine.
- 2.
Drive the vehicle, and let the transmission shift through several gears.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
None.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, the A/T gear position indicator blinks and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the TCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on.
Conditions for clearing the DTC
The A/T gear position indicator comes off by turning the vehicle to the OFF (LOCK) mode. The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.