P0851 2015 GMC Sierra Code - Park/Neutral Position Switch Circuit Low Voltage
Quick Answer
The P0851 diagnostic trouble code (DTC) for a 2015 GMC Sierra indicates a problem with the Park/Neutral Position (PNP) switch circuit having low voltage. Common causes include Faulty Park/Neutral Position (PNP) switch, Damaged wiring or connectors in the PNP switch circuit, Corrosion or poor connections in the circuit. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0851 2015 GMC Sierra indicates Park/Neutral Position Switch Circuit Low Voltage.
- Common causes
- Common causes include Faulty Park/Neutral Position (PNP) switch, Damaged wiring or connectors in the PNP switch circuit, Corrosion or poor connections in the circuit.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0851 2015 GMC Sierra Description
The P0851 diagnostic trouble code (DTC) for a 2015 GMC Sierra indicates a problem with the Park/Neutral Position (PNP) switch circuit having low voltage. The PNP switch, also known as the transmission range sensor, is a crucial component that informs the vehicle's computer about the gear position (Park, Neutral, Drive, Reverse, etc.). When the PNP switch circuit detects low voltage, it means that the signal being sent to the vehicle's computer is weaker than expected, which can lead to issues with starting the vehicle, shifting gears, and other transmission-related functions.
Common Causes of P0851 2015 GMC Sierra
- Faulty Park/Neutral Position (PNP) switch
- Damaged wiring or connectors in the PNP switch circuit
- Corrosion or poor connections in the circuit
- Issues with the vehicle's computer or software
- Electrical problems such as a weak battery or alternator
Symptoms of P0851 2015 GMC Sierra
- Difficulty starting the engine
- Inability to shift gears smoothly
- Transmission getting stuck in one gear
- Dashboard warning light illuminated
- Vehicle may not start at all
How to Fix P0851 2015 GMC Sierra
- Begin by conducting a thorough inspection of the PNP switch, wiring, and connectors to identify any visible damage or corrosion.
- Test the PNP switch using a multimeter to check for proper voltage output in each gear position.
- Replace the PNP switch if it is found to be faulty, ensuring proper alignment and connection.
- Repair or replace any damaged wiring or connectors in the circuit.
- Clear the DTC using an OBD-II scanner and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P0851 2015 GMC Sierra
The typical repair costs for addressing a P0851 code on a 2015 GMC Sierra can range from $150 to $400, including parts and labor. However, the specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It is recommended to check local rates for a more accurate estimate. Keep in mind that rates in metropolitan areas or at dealerships may be higher, while independent shops often charge less.
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