P0931 – Gear Shift Lock Solenoid Control Circuit High

System: Powertrain | Standard: ISO/SAE Controlled | Fault type: Circuit High

Definition source: SAE J2012/J2012DA (industry standard)

DTC P0931 indicates the powertrain control system has detected a “high” electrical condition in the gear shift lock solenoid control circuit. In practical terms, the controlling module is seeing a signal higher than expected for that circuit, which commonly points to an electrical issue such as a short-to-power, an open ground path, or a control circuit that is being pulled high when it should not be. The exact logic used to set P0931, the solenoid’s wiring route, and the module strategy can vary by vehicle, so confirm connector views, pin functions, and test procedures in the correct service information before replacing parts.

What Does P0931 Mean?

P0931 – Gear Shift Lock Solenoid Control Circuit High means the powertrain control module (or a related control module, depending on vehicle architecture) detected a high-input condition on the circuit used to control the gear shift lock solenoid. The “circuit high” fault type is an electrical diagnosis: the module expects the control circuit to change states within an allowable electrical window, and it has identified the circuit as being driven or biased higher than intended. SAE J2012 defines how DTCs are structured; however, the meaning of this code is defined strictly by its official title/description: a high condition in the gear shift lock solenoid control circuit.

Quick Reference

• Subsystem: Gear shift lock solenoid control circuit (shift interlock control and its electrical command/feedback, as applicable).
• Common triggers: Short-to-power on the control wire, open/poor ground on the solenoid or driver circuit, connector pin damage, harness chafing, or an internal driver fault causing the circuit to remain high.
• Likely root-cause buckets: Wiring/connector faults, power/ground distribution issues, shift lock solenoid electrical fault, control module driver/circuit fault.
• Severity: Typically moderate; may affect ability to release the shifter from Park and can create safety/operational concerns depending on how the interlock behaves.
• First checks: Scan for related codes, verify brake lamp switch/brake input status (varies by vehicle), inspect connectors/harness near shifter and under-dash for damage, check fuses and grounds tied to the interlock circuit.
• Common mistakes: Replacing the solenoid or shifter assembly without verifying a short-to-power/open ground, skipping connector pin-fit checks, or ignoring power/ground integrity and module command data.

Theory of Operation

The gear shift lock solenoid is used to help prevent unintended shifting out of Park. When enabling conditions are met (which vary by vehicle and may include brake pedal input and ignition state), a control module commands the solenoid through a dedicated control circuit. Depending on design, the solenoid may be powered and controlled on the ground side by a driver transistor, or it may be ground-provided and controlled on the power side. Some systems also monitor the circuit state to confirm the commanded condition.

P0931 sets when the module detects the control circuit is electrically “high” when it should not be, or higher than its expected range during a command. This can occur if the control wire is shorted to a power source, if a ground path is open causing the circuit to float high, if a connector fault biases the circuit, or if the internal driver/monitoring circuitry is malfunctioning.

Symptoms

• Shifter locked: Shifter may not release from Park even when the normal release conditions are met.
• Intermittent release: Shift lock operation may work sometimes and fail other times, especially with vibration or movement of the console/under-dash harness.
• No solenoid sound: No audible/feelable actuation from the shift lock solenoid when attempting to shift.
• Warning light: Malfunction indicator lamp (MIL) or a powertrain warning may illuminate, depending on vehicle strategy.
• Stored code: P0931 may store as current or history, possibly alongside other power/ground or switch input codes.
• Park release override use: Manual shift-lock release may be needed to move the vehicle.

Common Causes

• Short-to-power in the gear shift lock solenoid control circuit (chafed harness contacting a B+ feed)
• Open or high-resistance ground path for the shift lock solenoid or its driver circuit, causing the control line to be pulled high
• Corroded, loose, backed-out, or damaged terminals at the shift lock solenoid connector or at the module connector (poor pin fit)
• Harness damage near high-movement areas (shifter assembly area, steering column area, or bulkhead pass-through; routing varies by vehicle)
• Incorrect power feed present on the control wire due to misrouted wiring/previous repairs (crossed circuits)
• Internal fault in the gear shift lock solenoid (coil or internal wiring fault that alters circuit behavior)
• Fault in the control module output driver for the solenoid control circuit (driver stuck high)
• Power/ground integrity issue affecting the controlling module (module supply or ground problem influencing output interpretation)
• Water intrusion/contamination in connectors leading to unintended voltage bridging between adjacent terminals

Diagnosis Steps

Tools typically needed include a scan tool capable of reading codes, freeze-frame, and relevant data items; a digital multimeter; a test light as appropriate; and basic back-probing tools. Access to vehicle-specific wiring diagrams and connector pinouts is important because circuit routing varies by vehicle. If available, a breakout lead set and a battery charger/maintainer help keep test conditions stable during extended checks.

1. Confirm the code and capture context: Verify P0931 is present. Record freeze-frame data and note when it sets (key on, brake applied, shifter moved, etc.). Check for additional powertrain or body-related codes that may affect shift interlock operation; address power/ground and communication-related codes first if present.
2. Check basic operating conditions: Verify the brake lamps function normally and the brake switch input is being recognized where applicable (design varies by vehicle). While P0931 is a circuit-high fault for the solenoid control circuit, confirming related enable inputs can prevent chasing a secondary symptom.
3. Perform a focused visual inspection: Inspect the shifter area harness and the shift lock solenoid connector for damage, pinched wiring, moisture, or aftermarket splices. Look for rub-through points and any signs of overheating. Inspect module-side connectors that contain the solenoid control circuit for water intrusion or terminal damage.
4. Clear codes and run a controlled recheck: Clear DTCs and attempt to reproduce the fault under the same conditions noted in freeze-frame (key on, brake applied, shifting attempts). If the code returns immediately, prioritize electrical checks for a hard fault (short-to-power or driver stuck high).
5. Use live data and output controls where supported: Monitor the scan tool data items related to shift lock command/status (naming varies by vehicle). If the scan tool supports actuator/output control, command the shift lock solenoid on/off and observe whether the reported state changes. Log data during the test rather than relying on momentary readings.
6. Check for unwanted voltage on the control circuit: With the connector(s) accessible, measure the control circuit behavior with the solenoid connected and then disconnected (key state and procedure vary by vehicle). A circuit-high condition is commonly caused by a short-to-power or a missing/poor ground reference. If the control line remains high when it should be inactive, isolate whether the source is in the harness or the module driver by separating connectors and retesting per wiring diagrams.
7. Verify power and ground integrity with voltage-drop testing: Perform voltage-drop tests on the solenoid feed and ground paths under load (commanded on, if possible). Excessive drop on the ground side can make the control circuit appear high. Repeat on the module grounds that support the driver circuit; poor module grounding can bias output readings. Use service information for where to place leads and what constitutes an acceptable result.
8. Check continuity and short-to-power in the harness: With the circuit powered down as required, test continuity of the control wire end-to-end and check for short-to-power between the control wire and adjacent power feeds. Pay special attention to areas where the harness flexes or contacts brackets. If a short is suspected, manipulate the harness while monitoring the meter to locate the fault.
9. Perform a wiggle test with logging: While monitoring the control circuit state (scan data or meter), wiggle the harness at the shifter assembly, connectors, and pass-through points. Intermittent terminal contact or insulation damage can cause the control line to spike high. Capture a log so you can correlate harness movement with the fault occurrence.
10. Evaluate the solenoid itself: Inspect the solenoid connector pins for spread or corrosion. Test the solenoid coil for being out of specification and for internal shorts per service information. If the circuit tests good but commanding the solenoid results in abnormal circuit behavior, the solenoid may be influencing the circuit in a way that triggers a high-input detection.
11. Assess the control module output driver: If the harness and solenoid test good and the control line is still driven high incorrectly, suspect a driver fault or module-side issue. Before replacement, recheck module powers/grounds and connector terminal integrity, and ensure no external short is feeding the control line. Follow service information for any module-specific pinpoint tests and post-repair relearn/setup requirements.

Professional tip: When chasing a circuit-high fault, isolate the circuit methodically: disconnect the load (solenoid) and, if needed, disconnect the module to determine whether the high condition originates from an external short-to-power, a biased ground/reference, or a module driver that is stuck high. Combine this isolation approach with voltage-drop testing under load to avoid replacing parts when the real problem is power/ground integrity.

Possible Fixes & Repair Costs

Repair costs for P0931 vary widely because the fault is a circuit-high electrical condition and the correct fix depends on where the high signal is being introduced (wiring, connectors, solenoid, or control module). Parts access, labor time, and the need for pinpoint testing also change the total.

• Repair or replace damaged wiring in the gear shift lock solenoid control circuit (focus on rubbed-through insulation, pinched harness sections, or prior repair splices)
• Clean, repair, or replace corroded/loose connectors and terminals (restore proper pin tension and correct any pushed-out pins)
• Correct a short-to-power condition in the control wire (isolate and repair the section contacting a power feed)
• Repair ground path issues that can drive the circuit “high” (ground eyelet service, connector ground terminal repair, or harness ground repair as applicable)
• Replace the gear shift lock solenoid if testing confirms an internal electrical fault that causes an abnormally high control signal behavior
• Repair a power feed or related fuse/relay issue if it is backfeeding the control circuit (design varies by vehicle)
• Relearn/initialization procedures after repair if required by service information (varies by vehicle)
• Replace the controlling module only after all power/ground and circuit integrity checks pass and the fault is proven to be internal to the module

Can I Still Drive With P0931?

P0931 can affect shift-interlock behavior, meaning the shifter may not release as expected or may behave inconsistently. Because this involves the ability to select gears safely, treat it as a safety-relevant fault. If you cannot reliably shift out of Park, must override the interlock, or any brake/shift warnings appear, avoid driving and have the vehicle diagnosed. If the vehicle shifts normally and no safety warnings are present, limited driving may be possible, but you should still address the code promptly and verify operation per service information.

What Happens If You Ignore P0931?

Ignoring P0931 can lead to intermittent or persistent inability to shift out of Park, unexpected need for shift-lock override use, and repeated warning indicators. Electrical circuit-high faults can worsen as wiring damage or terminal corrosion progresses, potentially creating additional faults or causing intermittent no-shift events at inconvenient times. Continued operation without fixing the root cause may also complicate diagnosis later due to heat, vibration, and further connector degradation.

Related Solenoid Gear Codes

Compare nearby solenoid gear trouble codes with similar definitions, fault patterns, and diagnostic paths.

• P0923 – Gear Shift Forward Actuator Circuit High
• P0930 – Gear Shift Lock Solenoid Control Circuit Low
• P0929 – Gear Shift Lock Solenoid Control Circuit Range/Performance
• P0958 – Auto Shift Manual Mode Circuit High
• P0953 – Auto Shift Manual Control Circuit High
• P0907 – Gate Select Position Circuit High

Key Takeaways

• P0931 indicates a Gear Shift Lock Solenoid Control Circuit High electrical condition, not a confirmed mechanical failure.
• Most root causes are in wiring, connectors, power/ground integrity, or short-to-power issues within the control circuit.
• Verify the fault with circuit testing (continuity, short-to-power checks, and voltage-drop tests) before replacing parts.
• Because the shift interlock is safety-related, prioritize diagnosis if shifting behavior is abnormal.
• Module replacement should be a last step after circuit integrity and component tests confirm it.

Vehicles Commonly Affected by P0931

• Vehicles equipped with an electronically controlled automatic transmission and a brake-to-shift interlock system
• Vehicles using a body or powertrain controller to command a shift-lock solenoid through a dedicated control circuit
• Vehicles with console or column shifters that rely on an electrical shift interlock for Park release
• Vehicles frequently exposed to moisture, debris, or spills around the shifter area (connector contamination risk)
• High-mileage vehicles where harness flexing and vibration can degrade terminal tension over time
• Vehicles with recent interior, console, or shifter assembly service where connectors may be disturbed
• Vehicles with prior electrical repairs near the shifter, brake switch, or under-dash harness routing
• Vehicles operated in high-corrosion environments where ground points and connectors are prone to oxidation

FAQ

Does P0931 mean the gear shift lock solenoid is bad?

No. P0931 means the control circuit is being detected as “high” electrically. A solenoid could be involved, but circuit-high faults are often caused by wiring damage, connector issues, a short-to-power, or power/ground problems. Confirm with electrical testing before replacing the solenoid.

What is a “circuit high” fault in plain terms?

“Circuit high” means the control module is seeing a higher-than-expected electrical signal on the gear shift lock solenoid control circuit. This commonly happens from a short to a power feed, an open or poor ground reference (depending on design), or a control driver/output issue.

Can a brake switch problem cause P0931?

It can, depending on vehicle design. The shift interlock often depends on brake-related inputs, and a wiring fault or backfeed in related circuits could contribute to an unexpected high signal on the solenoid control circuit. Use service information and wiring diagrams to confirm how the circuits are linked on your vehicle.

Why does the code come and go?

Intermittent circuit-high conditions are commonly caused by loose terminals, harness chafing that only contacts power under vibration, or connector contamination that changes with temperature and movement. Performing a careful wiggle test and logging relevant data while commanding the solenoid can help locate the intermittent point.

What should I check first before replacing parts?

Start with a visual inspection of the shifter-area connector(s), harness routing, and grounds; then verify circuit integrity with short-to-power checks and voltage-drop testing on power and ground paths (as applicable). Only replace components after the circuit tests prove the component is the source of the high input.

Always confirm wiring routes, connector pinouts, and required post-repair procedures in the correct service information for your specific vehicle, since shift-interlock circuit designs and control strategies vary by vehicle.