DTC P074C
DTC P074C: Unable to Engage Gear 4
General Description
When shifting from 8th gear to 4th with the dog clutch A and F, the transmission control module (TCM) monitors values on the hydraulic pressure sensor and the operating status of the dog clutch. The TCM sets a failure code if the following condition occurs:
- The values on the hydraulic pressure sensor show that the dog clutch is not engaged properly while shifting from 8th to 4th.
- The gear is not operated for a certain time after shifting from 8th to 4th.
- The gear is shifted down to the 3rd with a gear ratio fault after shifting from 8th to 4th.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | Depending on the driving conditions |
| DTC Type | One drive cycle, MIL on, A/T gear position indicator blinks |
*: MIL comes on at second drive cycle
Enable Conditions
| Condition | ||
|---|---|---|
| Vehicle | Shifting from 8th gear to 4th with the dog clutch A and F. | |
Malfunction Threshold
The actual gear ratio is higher or lower than a specified value when the gear is shifted down to the 3rd after shifting from 8th to 4th with the dog clutch A and F.
The abnormality on this monitor is not a failure of parts. If there is any failure of parts, failure detection is done on a dedicated monitor and a failure warning lamp is let.
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.