P0812 - Transmission Range Sensor Performance Problem in Ford and GM Vehicles

Quick Answer

P0812 means: P0812 indicates a malfunction with the transmission range sensor which affects gear detection.

Fix: Check and replace faulty components Cost: $150 - $300 Time: 90-180 minutes

Can I drive with P0812? Immediate attention is recommended to prevent transmission damage.

Common Questions

What does P0812 mean and how does it affect my car?

P0812 indicates a problem with the transmission range sensor, which may lead to erratic shifting or potentially prevent your vehicle from moving. It is essential to address this issue promptly to avoid further damage.

What are the most common causes of P0812 and how much does it cost to fix?

Common causes include a faulty transmission range sensor, poor electrical connections, or software issues. Repair costs can range from $150 to $300, depending on whether parts need to be replaced or repaired.

Can I drive my car with P0812 or should I stop immediately?

It's best to stop driving the vehicle immediately, as continuing to drive with a P0812 code can cause further transmission damage or lead to complete failure.

How can I diagnose P0812 myself using GeekOBD APP?

Using the GeekOBD APP, connect via Bluetooth to retrieve diagnostic codes and freeze frame data. Look for P0812 and any related codes to pinpoint the issue, and check the status of the transmission range sensor.

What vehicles are most commonly affected by P0812?

P0812 is often found in 2010-2015 Ford Fusion and 2007-2012 Chevrolet Malibu. It’s advisable to check for any recalls or technical service bulletins (TSBs) related to your specific vehicle.

How can I prevent P0812 from happening again?

Regular maintenance of the transmission, including fluid changes and inspections of electrical connections, can help prevent issues with the range sensor. Additionally, ensuring software updates for the ECM may be beneficial.

What is P0812?

The diagnostic trouble code (DTC) P0812 indicates that there is an issue with the transmission range sensor, also known as the transmission position sensor. This component informs the engine control module (ECM) about the current gear selected in vehicles with automatic transmissions. When the ECM detects a discrepancy between the expected and actual position of the transmission, it triggers the P0812 code. Commonly found in models such as the 2010-2015 Ford Fusion and the 2007-2012 Chevrolet Malibu, this code can lead to serious performance issues. Drivers may notice erratic shifting, difficulty in changing gears, or even the inability to move the vehicle altogether. Moreover, the check engine light will illuminate, prompting drivers to seek immediate attention. Ignoring this code could result in further damage to the transmission or even a complete failure, leading to expensive repairs. It's crucial to address this issue promptly, ensuring that the transmission functions smoothly and efficiently for safe vehicle operation.

System: P - Powertrain (Engine, Transmission, Emissions)

Symptoms

Common symptoms when P0812 is present:

  • The check engine light remains illuminated, indicating a fault in the transmission system.
  • Drivers may experience harsh or erratic shifting, causing the car to jerk during gear changes.
  • There could be a noticeable decrease in fuel efficiency, as the transmission struggles to find the correct gear.
  • The vehicle may not go into gear at all, making it impossible to drive.
  • In some cases, drivers report unusual noises from the transmission, such as grinding or whining sounds.

Possible Causes

Most common causes of P0812 (ordered by frequency):

  1. The most common cause of P0812 is a faulty transmission range sensor, which accounts for about 60% of cases. This sensor can wear out over time or fail due to exposure to heat and vibration.
  2. Another cause could be poor electrical connections, such as corroded wiring or loose connectors that disrupt communication between the sensor and the ECM.
  3. Software glitches in the ECM can sometimes trigger P0812, especially if the vehicle has not had recent updates or if there are compatibility issues.
  4. Less common but serious causes include transmission fluid leaks that lead to low fluid levels, affecting the transmission's ability to shift properly.
  5. In rare cases, a complete transmission failure can lead to the P0812 code, necessitating significant repairs or replacement.

P0812 Repair Costs

Cost Breakdown by Repair Type

Transmission Range Sensor Replacement

Replacing the faulty transmission range sensor to restore proper function.

  • Total: $150 - $300
  • Success rate: 90%
Electrical Connector Repair

Repairing or replacing corroded connectors to ensure proper electrical signals.

  • Total: $50 - $150
  • Success rate: 80%
Money-Saving Tips for P0812
  • Start with the most common and least expensive repairs first
  • Use GeekOBD APP to confirm diagnosis before replacing expensive parts
  • Consider preventive maintenance to avoid future occurrences
  • Compare prices for OEM vs aftermarket parts based on your needs
  • Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional P0812 Diagnosis Process

Follow these systematic steps to accurately diagnose P0812. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)

Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)

Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the transmission range sensor for proper voltage and ground (20-30 minutes)

Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the transmission range sensor for proper voltage and ground (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: System function test - Verify proper operation after repairs and clear codes using the GeekOBD APP (10-15 minutes)

Step 4: System function test - Verify proper operation after repairs and clear codes using the GeekOBD APP (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and check for any reoccurring codes (15-20 minutes)

Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and check for any reoccurring codes (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

Important Notes

  • Always verify the repair with GeekOBD APP after completing diagnostic steps
  • Clear codes and test drive to ensure the problem is resolved
  • Address underlying causes to prevent code recurrence

Real Repair Case Studies

Case Study 1: Transmission Range Sensor Replacement in 2012 Ford Fusion

Vehicle: 2012 Ford Fusion, 85,000 miles

Problem: Customer reported check engine light on and harsh shifting.

Diagnosis: After scanning with GeekOBD APP, P0812 was identified. Visual inspection confirmed a faulty transmission range sensor.

Solution: Replaced the transmission range sensor and cleared the code.

Cost: $225 (sensor: $175, labor: $50)

Result: The vehicle shifted smoothly post-repair with no reoccurring codes.

Case Study 2: Electrical Connector Repair in 2009 Chevrolet Malibu

Vehicle: 2009 Chevrolet Malibu, 100,000 miles

Problem: Customer noticed the vehicle would not shift into gear.

Diagnosis: P0812 was present. Further inspection revealed corroded connectors.

Solution: Repaired the electrical connectors and tested the range sensor.

Cost: $125 (connector repair: $75, labor: $50)

Result: The vehicle operated normally after the repair with no issues.

Diagnose P0812

Use GeekOBD APP for professional diagnosis!

  • Real-time data monitoring
  • Advanced diagnostic features
  • Step-by-step repair guidance
  • Professional-grade analysis
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Code Information

Code: P0812
System: Powertrain (Engine, Transmission, Emissions)
Severity: HIGH
Category: Engine Codes