Gear Shift Lock Solenoid Control Circuit Low
Diagnostic trouble code P0930 indicates that the powertrain control module (PCM) or transmission control module (TCM) has detected a low voltage condition in the gear shift lock solenoid control circuit. This means the circuit voltage fell below the manufacturer's specified threshold, indicating a potential short to ground or an open circuit in the shift interlock system.
While not immediately dangerous while driving, this code often prevents the vehicle from being shifted out of Park, which can leave you stranded. It should be diagnosed and repaired promptly to restore normal vehicle operation.
Common symptoms
- Illuminated Check Engine Light
- Inability to shift out of Park
- Gear shift lever feels stuck or locked
- Brake pedal switch may not release the shift interlock
- Transmission may be stuck in a default or limp mode
Likely causes
- Faulty gear shift lock solenoid
- Short to ground or open in the shift lock solenoid wiring harness
- Corroded or damaged electrical connectors in the shift lock circuit
- Faulty brake light switch (which signals the shift lock to release)
- Blown fuse related to the shift interlock system
- Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM) (rare)
What to check before replacing parts
Check the relevant fuses for the shift interlock and brake light circuits.
Look for: A blown fuse indicates a short circuit that needs to be traced. If the fuse is blown, replace it and see if it blows again when pressing the brake pedal.
Verify the operation of the brake light switch.
Look for: Ensure the brake lights illuminate when the pedal is pressed. If they do not, the brake switch may be faulty, preventing the signal from reaching the shift lock solenoid.
Visually inspect the wiring and connectors leading to the gear shift lock solenoid.
Look for: Look for chafed wires, melted insulation, or corroded pins that could cause a short to ground or an open circuit.
Test the gear shift lock solenoid for proper resistance using a digital multimeter.
Look for: Compare the measured resistance to the manufacturer's specifications. An out-of-spec reading (often very low or infinite) indicates an internal failure of the solenoid.
Check for voltage and ground at the shift lock solenoid connector while pressing the brake pedal.
Look for: You should see battery voltage and a good ground when the brake is applied. If voltage is missing, trace the circuit back to the TCM/PCM or brake switch to find the open or short.
This page explains the generic P0930 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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