What Does P0923 Mean?
The TCM has detected that the gear shift forward actuator circuit voltage exceeds the expected range. This high voltage condition indicates a short to battery voltage in the actuator wiring, an open ground path, or a failed relay/driver. The forward actuator controls movement toward odd-numbered gears in automated manual transmissions.
Safety Warning
A high circuit may cause unintended actuator engagement or continuous current flow, potentially damaging the actuator or engaging gears unexpectedly. Do not drive; tow for repair.
Common Causes
35%
Short to battery voltage in forward actuator wiring
30%
Open ground circuit at forward actuator or in harness
20%
Forward actuator relay stuck closed/welded contacts
15%
TCM output driver fault stuck in high state
Diagnostic Steps
1
Step 1: With key on and actuator not commanded, measure voltage at the forward actuator connector — should be 0V; battery voltage present indicates a short to power or stuck relay.
2
Step 2: Verify actuator ground continuity — measure from ground pin at actuator connector to chassis ground; should be less than 1 ohm.
3
Step 3: Disconnect the actuator and recheck — if voltage drops, actuator is internally failed; if voltage remains, fault is in harness or TCM.
4
Step 4: Inspect harness routing for contact with battery cables, alternator output wire, or other power sources.
5
Step 5: If equipped with an actuator relay, remove it and check if the high voltage clears — welded relay contacts are a common failure mode.
Estimated Repair Cost
$150 - $1,200
Parts + labor, varies by vehicle and location
The TCM has detected that the gear shift forward actuator circuit voltage exceeds the expected range. This high voltage condition indicates a short to battery voltage in the actuator wiring, an open ground path, or a failed relay/driver. The forward actuator controls movement toward odd-numbered gea...
The most common cause of P0923 (Gear Shift Forward Actuator Circuit High) is: Short to battery voltage in forward actuator wiring
Typical repair costs for P0923 range from $150 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A high circuit may cause unintended actuator engagement or continuous current flow, potentially damaging the actuator or engaging gears unexpectedly. Do not drive; tow for repair.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0923 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automated Manual Transmission (Shift Control)
Difficulty
Type
Generic (SAE)
Recommended Tools
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