P0851 Pontiac Code - Park/Neutral Position Switch Circuit Low Voltage
Quick Answer
The P0851 diagnostic trouble code (DTC) for Pontiac vehicles indicates a problem with the Park/Neutral Position (PNP) switch circuit, specifically a low voltage condition. Common causes include Faulty PNP switch, Damaged wiring or connectors in the PNP switch circuit, Corrosion or moisture in the PNP switch 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 Pontiac indicates Park/Neutral Position Switch Circuit Low Voltage.
- Common causes
- Common causes include Faulty PNP switch, Damaged wiring or connectors in the PNP switch circuit, Corrosion or moisture in the PNP switch 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 Pontiac Description
The P0851 diagnostic trouble code (DTC) for Pontiac vehicles indicates a problem with the Park/Neutral Position (PNP) switch circuit, specifically a low voltage condition. The PNP switch, also known as the transmission range sensor, is responsible for detecting the gear position of the vehicle, allowing it to start only in Park or Neutral. When the PNP switch circuit detects a low voltage signal, it can lead to issues with starting the vehicle, shifting gears, and other transmission-related functions.
Common Causes of P0851 Pontiac
- Faulty PNP switch
- Damaged wiring or connectors in the PNP switch circuit
- Corrosion or moisture in the PNP switch circuit
- Issues with the transmission control module (TCM)
- Electrical system problems affecting voltage supply to the PNP switch
Symptoms of P0851 Pontiac
- Difficulty starting the vehicle
- Inability to shift out of Park
- Intermittent stalling while driving
- Dashboard warning lights related to transmission
- Erratic behavior in gear shifting
How to Fix P0851 Pontiac
- Begin by diagnosing the exact cause of the low voltage condition, using a digital multimeter to test the voltage at the PNP switch.
- Inspect the wiring and connectors in the PNP switch circuit for any signs of damage, corrosion, or loose connections.
- Replace the PNP switch if it is found to be faulty, ensuring proper alignment and adjustment during installation.
- Clear the DTC using an OBD-II scanner and perform a test drive to confirm that the issue has been resolved.
- If the problem persists, further diagnostics may be necessary to identify any underlying issues with the TCM or other related components.
Cost to Fix P0851 Pontiac
The cost of repairing a P0851 code on a Pontiac can vary depending on the specific cause of the issue and the labor rates in your area. In general, replacing a faulty PNP switch can range from $150 to $300, including parts and labor. Additional diagnostic time and potential repairs to other components may increase the total cost. It is recommended to consult with a trusted mechanic or dealership for a more accurate estimate based on your vehicle's make and model.
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Frequently Asked Questions about P0851 Pontiac Code
1. What does the OBDII code P0851 mean for a Pontiac?
P0851 indicates a low voltage issue in the Park/Neutral Position Switch Circuit, which helps the vehicle recognize when it's in park or neutral.
2. What are common symptoms of P0851 in a Pontiac?
Symptoms include difficulty starting the vehicle, improper gear engagement, or the transmission behaving erratically.
3. What causes the P0851 code to appear in a Pontiac?
Common causes include a faulty Park/Neutral position switch, damaged wiring or connectors, or low battery voltage.
4. Can the P0851 code affect my Pontiac’s drivability?
Yes, it can cause issues with shifting gears or prevent the vehicle from starting properly.
5. How do you diagnose the P0851 code in a Pontiac?
Diagnosis involves checking the Park/Neutral position switch, inspecting wiring and connectors for damage, and verifying voltage levels in the circuit.
6. Is it safe to drive a Pontiac with the P0851 code?
It is not recommended, as the code can lead to unpredictable transmission behavior and starting issues.
7. How can you fix the P0851 code in a Pontiac?
Repairs may include replacing the Park/Neutral position switch, repairing damaged wiring, or ensuring proper voltage is supplied to the circuit.
8. Can a low battery cause the P0851 code in a Pontiac?
Yes, insufficient battery voltage can contribute to the low voltage in the Park/Neutral position switch circuit.
9. How much does it typically cost to repair the P0851 code in a Pontiac?
Costs vary, but replacing the Park/Neutral position switch can range from $100 to $300, depending on parts and labor.
10. Can I clear the P0851 code without fixing the issue?
Clearing the code without addressing the underlying problem may cause it to reappear and could lead to further complications.
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