P0851 2017 GMC Sierra Code - Park/Neutral Position Switch Circuit Low Voltage
Quick Answer
The P0851 diagnostic trouble code (DTC) for a 2017 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 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 2017 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 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 2017 GMC Sierra Description
The P0851 diagnostic trouble code (DTC) for a 2017 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 there is an issue with the signal being sent to the vehicle's control module, potentially causing incorrect gear selection or preventing the vehicle from starting.
Common Causes of P0851 2017 GMC Sierra
- Faulty Park/Neutral Position (PNP) switch
- Damaged wiring or connectors in the circuit
- Corrosion or poor connections in the circuit
- Issues with the vehicle's control module
- Electrical system problems
Symptoms of P0851 2017 GMC Sierra
- Difficulty starting the vehicle
- Incorrect gear selection or erratic shifting
- Inability to shift out of Park
- Check Engine Light illuminated
- Transmission slipping or harsh shifting
How to Fix P0851 2017 GMC Sierra
- Diagnose the issue using a scan tool to confirm the P0851 code and identify the specific cause of the low voltage in the PNP switch circuit.
- Inspect the wiring and connectors for any damage, corrosion, or poor connections. Repair or replace as necessary.
- Test the PNP switch for proper operation and replace if faulty.
- Clear the DTC and test drive the vehicle to ensure the issue has been resolved.
- If the problem persists, further diagnosis may be required to identify any underlying issues with the control module or other components.
Cost to Fix P0851 2017 GMC Sierra
The typical repair costs for addressing a P0851 code in a 2017 GMC Sierra can vary depending on the specific cause of the issue. On average, the parts for a new PNP switch can range from $50 to $200, while labor costs can range from $100 to $300. Overall, the total repair cost could be between $150 and $500. It's important to note that these are rough estimates, and actual costs may vary based on factors such as location, vehicle make and model, and labor rates at auto repair shops. It's recommended to consult with a professional mechanic for a more accurate cost estimate.
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