Powertrain, generic · Transmission

P0927 Gear Shift Reverse Actuator Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Set when the drive circuit of the reverse shift actuator of an automated manual gearbox shows a voltage that is too high for the current switching state. Common reasons are a valve or motor line shorted to battery voltage or a driver stage that no longer switches off; on some circuit designs an open load also reads high. No manufacturer documents this code publicly. A ZF patent describes double-acting shift cylinders with a 3/2 solenoid valve on each chamber, and an Isuzu patent reverses an electric shift motor according to shift direction, so the reverse direction has its own output. CARB requires circuit checks on outputs. P0926 is the opposite low fault, P0924 the open circuit, P0923 the forward direction. A permanently energised actuator can force a gear, so shifting is usually locked.

Likely causes

Drive wire shorted to battery voltage
Driver stage in the control module stuck on
Open coil or winding read as high on some circuit designs

Symptoms

  • Transmission warning light on
  • Gearbox locks in one gear or refuses to shift
  • Possible grinding when a gear is pushed unintentionally

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–2,000
Time0.5–5 h

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

Parts involved

gear shift reverse actuatorwiring harnesstcm

Related codes

P0924P0925P0926P0923

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