Powertrain, generic · Transmission

P0926 Gear Shift Reverse Actuator Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Set when the drive circuit of the reverse shift actuator of an automated manual gearbox, the one moving the shift mechanism opposite to the forward direction, shows a voltage that is too low for the current switching state. This usually means a valve or motor line shorted to ground or an internal short in the actuator; the module often switches the output off to protect itself. No manufacturer documents this code publicly. A ZF patent drives each chamber of a double-acting shift cylinder through its own solenoid valve, an Isuzu patent runs the shift motor in both directions. CARB requires circuit checks on outputs. P0927 is the opposite high fault, P0924 the open circuit, P0922 the forward direction. Gears in this direction are blocked.

Likely causes

Drive wire chafed through and shorted to ground
Internal short in solenoid coil or shift motor
Water or corrosion bridging pins in the connector

Symptoms

  • Transmission warning light on
  • Certain gears can no longer be engaged
  • Gearbox may stay in neutral or hold one gear

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

P0924P0925P0927P0922

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