OBD-II trouble code
P0927: Gear Shift Reverse Actuator Circuit High
The reverse actuator circuit is reading high. Unlike the rest of this family it can usually be reproduced standing still in the workshop, because a high reading is what an idle circuit looks like — which is also why it overlaps confusingly with the open-circuit code.
Quick facts
- System
- Powertrain
- Category
- Transmission / Shift Control
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $30 – $3,000
- DIY difficulty
- Shop recommended
What does P0927 mean?
P0927 sets when the transmission control module reads the gear shift reverse actuator circuit above its acceptable window. It belongs to the same directional block as the other reverse actuator codes, but the way it is detected sets it apart from all of them.
Start with what a high reading physically means on an output like this. The module does not simply wait until it is driving the actuator to look at the circuit. Most modules apply a small monitoring current to their outputs and check the resulting potential, so an output with an intact load pulls down to a predictable level and an output with nothing attached is pulled up toward supply. That is a circuit-integrity check, it does not require the actuator to be commanded, and it typically runs at key-on. The practical consequence is unusual in this family: P0927 is the reverse-side code you can reproduce in the bay, standing still, on a car that has not been driven. Where the low code has to be hunted by commanding the actuator dozens of times and the performance code demands an overnight cold soak, this one is generally sitting there on the scan tool the moment the ignition goes on.
The same mechanism explains a real diagnostic trap. Because a missing load reads high, an open circuit and a high circuit can be the same physical fault seen by two different monitors — one module reporting a broken conductor as an open, another reporting it as a pin sitting at supply potential. If both codes are stored together, do not treat them as two problems. Check first whether the actuator is actually connected and whether its winding is continuous, because a disconnected or internally open motor produces exactly this reading with nothing wrong on the module side at all.
When the load is confirmed present and the circuit still reads high, the remaining candidates are the ones that genuinely put the pin at supply potential: a control conductor touching a permanently live wire, a motor winding shorted to its supply leg, or an output driver inside the module that has failed toward supply. Sorting those is a two-minute job. Disconnect the actuator, command the circuit off, and read the output with nothing on it. A pin that still sits high with the load removed is the module. A pin that behaves correctly unloaded sends you back to the harness or the motor.
One routine cause deserves its place at the front of the list because it is cheap and frequently missed: the supply fuse for the actuator assembly. With that feed open, the module can see an unexpected potential on the circuit and store a high code, and actuators have been replaced over a blown fuse more than once. Replace it, certainly — but find out what opened it first, because a fuse that has blown once will blow again for the same reason.
Common causes
- Reverse actuator disconnected or its winding open, leaving the output unloaded
- Blown fuse in the reverse actuator supply circuit
- Control conductor shorted to a permanently powered wire in the loom
- Actuator motor winding shorted internally to a supply leg
- Output driver inside the transmission control module failed toward supply
- Corroded connector allowing tracking between powered and control terminals
- Moisture intrusion bridging terminals in a rarely-disturbed connector
- Open return path leaving the circuit floating at supply potential
- Terminal backed out of the connector body after previous work
- Damage from a jump start or reverse polarity event affecting the output stage
Symptoms
- Fault present and readable at key-on without driving the vehicle
- No reverse gear while all forward gears operate normally
- Warning lamp with a transmission fault message
- Reverse actuator open-circuit code stored alongside this one
- Reversing camera and park assist features not activating
- Fault remaining present with the actuator disconnected
- Gear indicator refusing to show R when reverse is selected
- Fault appearing immediately after work in the transmission area
- Blown fuse found in the transmission actuator supply circuit
- Code returning promptly after being cleared, without a road test
Diagnostic steps
- 1.Check the code at key-on before driving, since this is the one code in the reverse family that usually reports itself on a stationary vehicle.
- 2.Confirm the actuator is connected and its winding is continuous before anything else, because a missing load reads high on its own.
- 3.If an open-circuit code is stored alongside, treat both as one fault and prove the load first rather than diagnosing two problems.
- 4.Disconnect the actuator, command the circuit off, and read the output unloaded — a pin still high with no load is a failed driver.
- 5.Check the reverse actuator supply fuse, and if it has opened, find the cause before fitting a replacement.
- 6.Measure the motor winding to each supply leg with the harness disconnected to find an internal short to power.
- 7.Inspect the connector for tracking, moisture and corrosion between powered and control terminals.
- 8.Confirm terminal retention with a matching pin, since a terminal backed out of the body presents as an unloaded output.
- 9.Trace the control conductor for contact with a permanently live wire, prioritising any repaired or rerouted section.
- 10.Verify the return path is intact, because an open return can leave the output floating toward supply and mimic a short to power.
Repair cost
$30 – $3,000
The low end of this range is genuine and unusual for the family: a blown supply fuse plus the diagnosis to find why it opened can settle at $30 to $250. Diagnosis alone is $150 to $400, and less of it is spent hunting than on the other reverse codes because the fault is usually present at key-on. A shorted or chafed control conductor repaired properly is $140 to $600. A reverse actuator replaced as an external serviceable unit is $450 to $1,500 fitted with adaptation, rising to $1,700 to $3,000 where the transmission must come out. A transmission control module with a failed output stage is $900 to $2,200 with coding, and on a high-side fault that outcome is a realistic early suspect rather than a last resort.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with gear shift reverse actuator replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.