Powertrain, generic · Transmission

P0925 Gear Shift Reverse Actuator Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

Plausibility fault in the drive circuit of the reverse shift actuator of an automated manual gearbox, the actuator that moves the shift mechanism opposite to the forward direction. The circuit is neither open nor shorted, but current, voltage or the resulting shift movement do not match the command. No manufacturer documents this code publicly. A Hyundai/Kia patent detects jammed shift actuators from rising motor current, and a ZF patent shows double-acting shift cylinders with one solenoid valve per chamber, so each direction can be judged on its own. CARB requires functional checks on such outputs. P0924, P0926 and P0927 are the clear electrical faults, P0921 the forward direction, P0919 the missed target. Shifts in this direction become slow or fail.

Likely causes

Sticking shift valve, worn shift motor or stiff shift linkage
Solenoid or motor resistance out of specification
Increased contact resistance in connector or wiring
Insufficient hydraulic pressure on hydraulic units

Symptoms

  • Transmission warning light on
  • Slow, harsh or aborted gear changes in one direction
  • Fallback mode with fewer available gears

Repair estimate

DifficultyHardWorkshop job
Parts and labour€150–2,000
Time1–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

gear shift reverse actuatorwiring harnesstcm

Related codes

P0924P0926P0927P0921P0919

References: law.cornell.edu, patents.google.com, patents.google.com.