A faulty reverse shift actuator solenoid or motor, which may have an open winding or internal short.; Damaged or corroded wiring harness or connector at the transmission, causing high resistance or an open circuit.; A short to ground in the actuator control circuit, often due to chafed wires or moisture intrusion.; A failed transmission control module (TCM) or PCM driver circuit, though this is less common.; Low transmission fluid level or contaminated fluid, which can affect actuator operation and circuit feedback.; Poor electrical connections at the battery or ground points, leading to voltage drops that affect the circuit.

DTC codes / P09xx · Transmission / P0926

P0926Gear Shift Reverse Actuator Circuit Low

Q: What does code P0926 mean?

Gear Shift Reverse Actuator Circuit Low. P0926 indicates that the powertrain control module (PCM) has detected an abnormally low voltage or current on the electrical circuit that controls the reverse gear shift actuator, which is typically a solenoid or motor responsible for engaging reverse gear in an automatic transmission. The PCM monitors this circuit and sets the code when the signal falls below the expected threshold, indicating a short to ground, an open circuit, or a faulty actuator.

P0926 indicates that the powertrain control module (PCM) has detected an abnormally low voltage or current on the electrical circuit that controls the reverse gear shift actuator, which is typically a solenoid or motor responsible for engaging reverse gear in an automatic transmission. The PCM monitors this circuit and sets the code when the signal falls below the expected threshold, indicating a short to ground, an open circuit, or a faulty actuator.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaTransmission

Symptoms you may notice

The check engine light or transmission warning light illuminates on the dashboard.
The transmission may fail to engage reverse gear when selected, or engagement may be delayed or harsh.
The vehicle may default to a limp-home mode, limiting speed and gear selection.
In some cases, the driver may notice no symptoms besides the warning light, especially if the fault is intermittent.
Other transmission-related codes may be stored, and the transmission may shift erratically in forward gears.

Common causes, most likely first

A faulty reverse shift actuator solenoid or motor, which may have an open winding or internal short.
Damaged or corroded wiring harness or connector at the transmission, causing high resistance or an open circuit.
A short to ground in the actuator control circuit, often due to chafed wires or moisture intrusion.
A failed transmission control module (TCM) or PCM driver circuit, though this is less common.
Low transmission fluid level or contaminated fluid, which can affect actuator operation and circuit feedback.
Poor electrical connections at the battery or ground points, leading to voltage drops that affect the circuit.

How to diagnose and fix it

Verify the code with a scan tool and check for any related transmission codes to understand the full context.
Inspect the transmission fluid level and condition; top off or replace fluid if necessary, as low fluid can cause actuator performance issues.
Visually inspect the wiring harness and connectors at the transmission for damage, corrosion, or loose pins; repair or replace as needed.
Disconnect the actuator and measure its resistance with a multimeter; compare to the manufacturer's specification to determine if it is faulty.
Check the control circuit for a short to ground or open circuit using a multimeter and wiring diagram; repair any wiring faults.
If the actuator tests bad, replace it and clear the code; if the circuit tests good, suspect the TCM or PCM and perform further diagnostics.
After repairs, clear the codes and take the vehicle for a test drive to verify that reverse gear engages properly and the code does not return.

Reverse Actuator Circuit Low: Hidden Causes

A low transmission fluid level can cause the reverse actuator to draw higher current than normal, setting a low circuit code even when the actuator itself is healthy.
Corrosion inside the transmission connector is a frequent culprit, especially in areas with road salt or high humidity, and can mimic a failed actuator.
The code may be set by a momentary voltage drop during engine cranking if the battery is weak, so always check battery and charging system health first.
Some vehicles use a single actuator for multiple gears, so a fault in the reverse circuit may also affect other gear engagements, but the code specifically flags the reverse circuit.
After replacing the actuator, a relearn or adaptation procedure may be required for the transmission to shift correctly, which is often overlooked.

Can I keep driving with P0926?

If the vehicle still engages reverse and drives normally, you can drive it to a repair shop, but avoid long trips and be prepared for the transmission to enter limp mode. If reverse is completely inoperative or the vehicle is stuck in limp mode, do not drive it and have it towed to avoid further transmission damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.