P0927

Code

Generic P — Powertrain

Gear Shift Reverse Actuator Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 24 EN: 41 RU: 29

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Page language: EN

Causes

Short to battery voltage on the reverse actuator power or signal wire
Open or damaged wiring causing abnormal voltage reading (pull-up to VB)
Corroded, loose or damaged connector at actuator or module
Failed reverse shift actuator (solenoid or position sensor)
Faulty PCM/TCM or internal driver failure
Aftermarket modifications or recent service damage to harness

Symptoms

Malfunction Indicator Lamp (MIL) or transmission warning lamp illuminated
Reverse gear may not engage or engages intermittently
Transmission stuck in limp or fail-safe mode
Incorrect gearbox display or shift indicator for reverse
Unusual clicking from transmission or actuator when commanded

What to check

Read and record freeze frame and all stored transmission/PCM codes with a scan tool
Visual inspection of actuator connector and wiring for corrosion, damage, or pin push-out
Backprobe actuator connector and measure DC voltages with key ON and with engine running
Check resistance of actuator coil/position sensor (compare to spec if available)
Wiggle test wiring while monitoring voltage/scan tool for changes or intermittent faults
Disconnect actuator and check for short to battery (voltage present at harness with actuator disconnected)

Signal parameters

Actuator power supply: typically battery voltage (~12 V) when commanded; should not be above battery voltage
Position/feedback sensor signals: typically 0–5 V range (vehicle-specific)
Coil resistance (solenoid): typically a few ohms to tens of ohms — consult vehicle spec
Expected idle/off condition: sensor signal within specified rest range; commanded condition: voltage changes per PCM command
High-level fault: measured voltage exceeds expected sensor range or is equal to constant battery voltage when not commanded

Diagnostic algorithm

Verify DTC and note freeze frame data. Clear code and attempt to re-create to confirm repeatability.
Perform a detailed visual inspection of the reverse actuator connector, wiring harness along routing to transmission and PCM/TCM, and all related grounds.
Backprobe the actuator connector. With key ON (engine OFF) measure supply, signal, and ground. Compare to expected ranges. Repeat while commanding the actuator with a scan tool.
If the signal shows battery voltage when it should not, disconnect the actuator. If the harness still shows high voltage with actuator disconnected, suspect a short to battery or module driver issue.
Measure coil or sensor resistance at the actuator. If out of specification, replace actuator.
Perform continuity checks from the actuator connector to the PCM/TCM for short-to-power, short-to-ground, and open circuits. Repair damaged wiring or connectors.
If wiring and actuator test good, recheck module grounds and reference voltages at the PCM/TCM. If module outputs are shorted or erratic, consider replacing or reprogramming the control module per manufacturer procedure.
After repairs, clear codes, test drive and verify the fault does not return. Re-scan to confirm no related codes remain.

Likely causes

Connector corrosion or bent pins at the actuator
Wire chafing or break near transmission or harness routing points
Shorted signal wire to constant 12 V
Failed actuator (internal short or sensor out-of-range)
Bad ground or reference voltage at control module

Fault status

⚠️ Status

P0927 — Gear Shift Reverse Actuator Circuit High: Control module detected an abnormally high voltage on the reverse gear actuator circuit (possible short to battery, wiring fault, or actuator/module failure).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours