Advanced Diagnostics

Advanced Diagnostics - DTC P1745: Problem in Shift Control System; Servo Control Valve Stuck OFF or Servo Valve Stuck OFF














General Description
The servo control valve and the servo valve are part of the control circuit of the transmission. The valves operate when the shift lever is in D or S due to line pressure, and they turn off when the shift lever is in P, R, or N. The powertrain control module (PCM) monitors the input shaft (mainshaft) speed and the output shaft (countershaft) speed at the gear change determined by the shift schedule. When an improper gear ratio output is compared to the predetermined gear change mode, the PCM detects a servo control valve OFF or servo valve OFF failure and stores a DTC.

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






Enable Conditions






Malfunction Threshold
One of these Symptoms occurs:










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, a Confirmed DTC and the freeze data are stored. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.