Advanced Diagnostics

Advanced Diagnostics-DTC P1734: Shift Error F

General Description











Hydraulic pressure to each clutch is controlled by a shift valve. The shift valve activates according to the ON/OFF status of shift solenoid valves A, B, C, D, and E. Hydraulic pressure supply in D is shown above. The line pressure or the A/T clutch pressure control solenoid valve A, B, or C pressure is supplied to each clutch by the activated shift valve. The powertrain control module (PCM) computes the actual ratio of input shaft (mainshaft) and output shaft (countershaft) revolutions. If a difference between the actual ratio and the commanded gear occurs when shifting to each gear position, the PCM detects a malfunction in A/T clutch pressure control solenoid valve, in the shift solenoid valve, or in the hydraulic system and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
Symptom 1-A or Symptom 1-B occurs.






Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

- Shift solenoid valve B stuck off
- Shift valve B stuck
- Shift solenoid valve C stuck off
- Shift valve C stuck

Confirmation Procedure

With the HDS
None.

With the Driving Pattern
1. Start the engine.
2. Drive the vehicle in D until the transmission shifts into 5th gear.

- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
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 or by disconnecting the battery.