Gear Shift Reverse Actuator Circuit/Open
The P0924 code indicates that the Transmission Control Module (TCM) has detected an open circuit or lack of electrical continuity in the gear shift reverse actuator circuit. The computer sets this code when it attempts to command the actuator to engage reverse gear but does not detect the expected electrical load or feedback voltage.
This code is highly urgent because it usually results in the complete loss of the reverse gear, severely limiting vehicle maneuverability. Driving should be minimized until the issue is repaired to prevent getting stranded in a position requiring reverse.
Common symptoms
- Inability to shift into reverse gear
- Illuminated Check Engine Light
- Transmission stuck in a forward gear or neutral
- Vehicle enters limp-home mode
- Erratic or harsh shifting behavior
Likely causes
- Damaged, broken, or disconnected wiring in the reverse actuator circuit
- Corroded, loose, or damaged electrical connectors at the actuator or TCM
- Faulty gear shift reverse actuator
- Blown fuse or tripped relay providing power to the actuator circuit
- Internal failure of the Transmission Control Module (TCM)
What to check before replacing parts
Visually inspect the wiring harness and connectors leading to the reverse gear actuator.
Look for: Look for broken wires, chafing, melted insulation, or corroded pins that would cause an open circuit.
Check the transmission system fuses and relays.
Look for: Identify any blown fuses or faulty relays that supply power to the transmission actuators, which would interrupt the circuit.
Measure the internal resistance of the gear shift reverse actuator using a digital multimeter.
Look for: Compare the resistance reading to the manufacturer's specifications; an infinite reading (OL) indicates an internal open circuit in the actuator.
Test for power and ground at the actuator connector with the key on, engine off (KOEO).
Look for: Verify that the actuator is receiving the correct reference voltage and has a solid ground; lack of voltage points to a wiring or TCM issue upstream.
Perform a bi-directional test using an advanced scan tool to command the reverse actuator.
Look for: Listen for the actuator clicking or engaging; if the scan tool shows the command is sent but no action occurs and wiring is good, the TCM or actuator is at fault.
This page explains the generic P0924 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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