When you shift your vehicle into Drive, a series of sensors detects the gear you have selected, then the cars computer commands an electric motor to engage a forward gear. If there is an abnormally high voltage signal coming from the gear shift forward actuator circuit, a P0923 DTC will be set.
How Serious is the Code?
A P0923 diagnostic trouble code means that you will probably not be able to engage a forward gear with the shifter, which can obviously render your vehicle undrivable.
Symptoms of a P0923 include:
- Erratic shifting behavior
- Transmission cannot go into or shift out of a forward gear
- Damaged wiring
- Broken or corroded connectors
- Bad gearshift forward actuator
- Broken gear guide rail
- Broken shift shaft
- Internal mechanical issues
- ECU/TCM issues or failure
How to Diagnose the Code?
When diagnosing a P0923 OBDII trouble code, a mechanic will need to carefully check all of the wires and connectors going to the gear shift actuator assembly. The gear shift actuator itself also need to be checked, along with the gear guide rail and shift shaft. Other possible causes of this OBD2 code are internal mechanical problems and ECU or TCM issues.
What Repairs Will Fix P0923?
- Repair or replace any damage wiring or connectors
- Replace gearshift forward actuator
- Repair or replace gear guide rail
- Repair or replace shift shaft
- Repair internal mechanical fault(s)
- Reprogram or replace ECU/TCM
- P0920 – Gear Shift Forward Actuator Circuit/Open
- P0921 – Gear Shift Forward Actuator Circuit Range/Performance
- P0922 – Gear Shift Forward Actuator Circuit Low
- P0924 – Gear Shift Reverse Actuator Circuit/Open
- P0925 – Gear Shift Reverse Actuator Circuit Range/Performance
- P0926 – Gear Shift Reverse Actuator Circuit Low
- P0927 – Gear Shift Reverse Actuator Circuit High