P0879 - Transmission Fluid Pressure Sensor Circuit Range/Performance Problem in Common Vehicles

Quick Answer

P0879 means: P0879 indicates a problem with the transmission fluid pressure sensor circuit, impacting shifting performance.

Fix: Check and replace faulty components Cost: $200 - $400 Time: 90-180 minutes

Can I drive with P0879? Immediate attention is advised to prevent further transmission damage.

Common Questions

What does P0879 mean and how does it affect my car?

The P0879 code indicates a problem with the transmission fluid pressure sensor circuit, which can lead to poor shifting performance and potential transmission damage. It can cause your car to hesitate, slip, or struggle to accelerate, impacting your overall driving experience.

What are the most common causes of P0879 and how much does it cost to fix?

The most common causes of a P0879 code include a faulty transmission fluid pressure sensor, damaged wiring, or low transmission fluid. Repair costs typically range from $100 to $400, depending on the specific issue and needed repairs.

Can I drive my car with P0879 or should I stop immediately?

While you may be able to drive your vehicle short distances, it's advisable to avoid driving until the issue is resolved. Continuing to drive can lead to severe transmission damage and more costly repairs.

How can I diagnose P0879 myself using GeekOBD APP?

Using the GeekOBD APP, start by scanning for trouble codes to confirm the P0879 code. Review freeze frame data to understand the conditions under which the code was triggered, and then proceed to visually inspect the sensor and wiring for damage.

What vehicles are most commonly affected by P0879?

Common vehicles affected by P0879 include the 2005-2015 Chevrolet Silverado, 2006-2014 Ford Explorer, and 2007-2015 Dodge Ram 1500. Always check for any recalls or technical service bulletins related to your specific model.

How can I prevent P0879 from happening again?

To prevent a P0879 code from recurring, regularly check your transmission fluid levels, change the fluid according to your manufacturer’s schedule, and inspect wiring and connections during routine maintenance.

What is P0879?

The diagnostic trouble code (DTC) P0879 indicates a transmission fluid pressure sensor circuit range or performance problem. This code typically appears when the powertrain control module (PCM) detects that the input from the transmission fluid pressure sensor is outside of the expected range. The transmission fluid pressure sensor is crucial for monitoring the hydraulic pressure within the transmission system, which directly affects shifting performance and overall vehicle driveability. When this sensor malfunctions, it can lead to improper transmission behavior, such as slipping, harsh shifts, or even failure to shift altogether. Common vehicles affected by this code include models from General Motors, Ford, and Chrysler, particularly those manufactured between 2005 and 2018. If left unresolved, a P0879 code can result in severe transmission damage, decreased fuel efficiency, and ultimately costly repairs. For drivers experiencing this code, it’s crucial to understand that immediate attention is necessary, as ignoring this issue can lead to more significant problems down the road.

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

Symptoms

Common symptoms when P0879 is present:

  • The check engine light remains illuminated, indicating a persistent issue that requires diagnosis.
  • Engine hesitates during acceleration, causing noticeable delays in response when pressing the gas pedal.
  • Fuel economy significantly decreases, often by 10-15%, due to inefficient transmission operations.
  • Shifting becomes harsh or erratic, causing uncomfortable driving experiences and potential safety concerns.
  • Transmission may slip, leading to a loss of power during driving, particularly noticeable during acceleration.

Possible Causes

Most common causes of P0879 (ordered by frequency):

  1. The most common cause of a P0879 code is a faulty transmission fluid pressure sensor, which occurs in approximately 60% of cases. This sensor can fail due to wear and tear or exposure to extreme temperatures.
  2. Another frequent cause can be damaged wiring or poor connections in the sensor circuit, often leading to intermittent issues that can confuse the PCM.
  3. The third cause involves low transmission fluid levels or degraded fluid, which can lead to improper sensor readings. Regular fluid checks and changes can help prevent this.
  4. Less commonly, a malfunctioning PCM can be the root cause, leading to incorrect readings from the sensor. This is rare but requires professional diagnosis.
  5. In rare instances, mechanical failures within the transmission itself, such as a stuck valve or pump issues, may trigger a P0879 code.

P0879 Repair Costs

Cost Breakdown by Repair Type

Transmission Fluid Pressure Sensor Replacement

Replacing the faulty sensor with a new OEM part.

  • Total: $200 - $400
  • Success rate: 85%
Wiring Repair

Repairing damaged wiring or connections to the sensor.

  • Total: $100 - $300
  • Success rate: 75%
Transmission Fluid Change

Changing the transmission fluid to ensure proper function.

  • Total: $150 - $250
  • Success rate: 65%
Money-Saving Tips for P0879
  • 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 P0879 Diagnosis Process

Follow these systematic steps to accurately diagnose P0879. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Initial visual inspection - Check for obvious signs of damage like frayed wiring or loose connections in the transmission fluid pressure sensor circuit (5-10 minutes)

Step 1: Initial visual inspection - Check for obvious signs of damage like frayed wiring or loose connections in the transmission fluid pressure sensor circuit (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 - Utilize the GeekOBD APP to retrieve all stored codes and freeze frame data, which provides context for the P0879 code (10-15 minutes)

Step 2: OBD2 scan with GeekOBD APP - Utilize the GeekOBD APP to retrieve all stored codes and freeze frame data, which provides context for the P0879 code (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 to test the transmission fluid pressure sensor and check for proper voltage and resistance levels (20-30 minutes)

Step 3: Component testing - Use a multimeter to test the transmission fluid pressure sensor and check for proper voltage and resistance levels (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 - After repairs, verify that the transmission operates correctly and clear the codes using the GeekOBD APP (10-15 minutes)

Step 4: System function test - After repairs, verify that the transmission operates correctly and clear the 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 ensure the transmission shifts smoothly and the P0879 code does not reappear (15-20 minutes)

Step 5: Road test verification - Drive the vehicle under various conditions to ensure the transmission shifts smoothly and the P0879 code does not reappear (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 Fluid Pressure Sensor Replacement for 2014 Chevrolet Silverado

Vehicle: 2014 Chevrolet Silverado 1500, 85,000 miles

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

Diagnosis: Performed OBD2 scan revealing P0879. Visual inspection found corroded wiring.

Solution: Replaced the transmission fluid pressure sensor and repaired wiring.

Cost: $350 (sensor: $200, labor: $150)

Result: Post-repair, the vehicle shifted smoothly and check engine light was cleared.

Case Study 2: Wiring Repair on 2010 Ford Explorer

Vehicle: 2010 Ford Explorer, 120,000 miles

Problem: Customer experienced engine hesitation and poor acceleration.

Diagnosis: OBD2 scan confirmed P0879. Wiring inspection revealed frayed wires.

Solution: Repaired damaged wiring and replaced transmission fluid.

Cost: $200 (wiring repair: $100, fluid: $100)

Result: Customer reported significant improvement in vehicle performance.

Diagnose P0879

Use GeekOBD APP for professional diagnosis!

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  • Step-by-step repair guidance
  • Professional-grade analysis
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Code Information

Code: P0879
System: Powertrain (Engine, Transmission, Emissions)
Severity: HIGH
Category: Engine Codes