Quick Answer
P0878 means: P0878 indicates a high input signal from the transmission fluid pressure sensor.
Can I drive with P0878? Immediate attention is advised to prevent serious transmission damage.
Common Questions
What does P0878 mean and how does it affect my car?
The P0878 code indicates a high input signal from the transmission fluid pressure sensor. If this code appears, it can lead to serious transmission problems, including slipping gears and erratic shifting, which can affect your vehicle's performance and safety. Ignoring this code could result in costly repairs down the line.
What are the most common causes of P0878 and how much does it cost to fix?
Common causes of P0878 include a faulty transmission fluid pressure sensor, damaged wiring, or low transmission fluid levels. Repair costs can range from $100 for wiring repairs to $300 for sensor replacement, depending on the specific issue.
Can I drive my car with P0878 or should I stop immediately?
While you may be able to drive with the P0878 code, it is not advisable to do so for long. Continuing to drive could lead to further transmission damage and more expensive repairs. It's best to address this issue as soon as possible.
How can I diagnose P0878 myself using GeekOBD APP?
To diagnose P0878 using the GeekOBD APP, connect the app to your vehicle's OBD2 port, run a scan to retrieve the DTCs, and check the freeze frame data for context. This will help you understand when the code was triggered and any related symptoms.
What vehicles are most commonly affected by P0878?
P0878 is commonly found in vehicles like the 2010-2018 Chevrolet Malibu and the 2014-2017 GMC Terrain. Be sure to check for any recalls or Technical Service Bulletins (TSBs) related to transmission issues in these models.
How can I prevent P0878 from happening again?
To prevent P0878 from recurring, regularly check your transmission fluid levels and replace the fluid as recommended by your vehicle's manufacturer. Additionally, perform routine inspections of the wiring and connections related to the transmission system.
What is P0878?
The P0878 diagnostic trouble code indicates an issue with the transmission fluid pressure sensor circuit, particularly a high input signal. This code typically arises in modern vehicles equipped with automatic transmissions, such as the 2010-2018 Chevrolet Malibu, 2014-2017 GMC Terrain, and the 2011-2016 Ford Explorer. When the vehicle's Engine Control Module (ECM) detects that the transmission fluid pressure sensor is reporting a higher voltage than expected, it triggers this code. This problem can lead to severe transmission issues if not addressed promptly, such as slipping gears, erratic shifting, or even complete transmission failure in extreme cases. Drivers may notice symptoms like a check engine light, difficulty shifting, or a decrease in fuel efficiency. It's crucial to diagnose and repair this issue as soon as possible to avoid costly repairs down the line. Regular maintenance, including checking the transmission fluid levels and replacing the fluid as recommended by the vehicle manufacturer, can help prevent this code from appearing. Understanding P0878 is essential for maintaining the health of your vehicle's transmission system.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P0878 is present:
- Check engine light illuminates, indicating an underlying issue that requires immediate attention.
- Transmission may slip during acceleration, causing unexpected shifts and a lack of power.
- Fuel economy may decrease significantly, often by 10-15%, as the engine works harder to compensate for transmission issues.
- Harsh or delayed shifting can be felt when the vehicle changes gears, leading to a rough driving experience.
- Unusual noises from the transmission area, such as grinding or whining sounds, can occur, indicating potential mechanical failure.
Possible Causes
Most common causes of P0878 (ordered by frequency):
- {'description': 'Faulty transmission fluid pressure sensor, which is the most common cause (about 50% likelihood). This sensor may fail due to age or exposure to extreme temperatures.', 'likelihood': '50%'}
- {'description': 'Damaged wiring or poor connections in the transmission fluid pressure sensor circuit can also trigger this code. Corrosion or frayed wires may disrupt the signal to the ECM.', 'likelihood': '30%'}
- {'description': 'Low transmission fluid levels can lead to inaccurate readings from the pressure sensor. Regular fluid checks can prevent this issue.', 'likelihood': '15%'}
- {'description': 'Internal transmission issues, such as pump failure or valve body complications, can cause erratic pressure readings and trigger the P0878 code.', 'likelihood': '4%'}
- {'description': 'Rarely, a failing ECM itself can lead to false readings and trigger this code, although this is less common.', 'likelihood': '1%'}
P0878 Repair Costs
Cost Breakdown by Repair Type
Replacing the Transmission Fluid Pressure Sensor
This option involves replacing the faulty pressure sensor, which is often the root cause of the P0878 code.
- Total: $150 - $300
- Success rate: 85%
Repairing Wiring and Connections
Repairing damaged wiring or connections in the pressure sensor circuit can resolve the issue without replacing the sensor.
- Total: $100 - $200
- Success rate: 75%
Transmission Fluid Flush
Performing a fluid flush and replacing the transmission fluid can help if low fluid levels are the issue.
- Total: $80 - $150
- Success rate: 70%
Money-Saving Tips for P0878
- 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 P0878 Diagnosis Process
Follow these systematic steps to accurately diagnose P0878. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Step 1: Initial visual inspection - Begin with a thorough visual inspection of the transmission area for obvious signs of wear or damage, such as frayed wiring or loose connections (5-10 minutes)
Step 1: Initial visual inspection - Begin with a thorough visual inspection of the transmission area for obvious signs of wear or damage, such as frayed wiring or loose connections (5-10 minutes).
Step 2: Step 2: OBD2 scan with GeekOBD APP - Use the GeekOBD APP to scan for DTCs and review freeze frame data to understand the context of the fault (10-15 minutes)
Step 2: OBD2 scan with GeekOBD APP - Use the GeekOBD APP to scan for DTCs and review freeze frame data to understand the context of the fault (10-15 minutes).
Step 3: Step 3: Component testing - Utilize a multimeter to test the transmission fluid pressure sensor and associated wiring for continuity and proper voltage (20-30 minutes)
Step 3: Component testing - Utilize a multimeter to test the transmission fluid pressure sensor and associated wiring for continuity and proper voltage (20-30 minutes).
Step 4: Step 4: System function test - After replacing any faulty components, conduct a function test to ensure the system operates correctly, clearing any codes (10-15 minutes)
Step 4: System function test - After replacing any faulty components, conduct a function test to ensure the system operates correctly, clearing any codes (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm that the issue is resolved and the check engine light has not returned (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm that the issue is resolved and the check engine light has not returned (15-20 minutes).
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: Chevrolet Malibu P0878 Repair Case Study
Vehicle: 2015 Chevrolet Malibu, 85,000 miles
Problem: Customer noticed the check engine light was on, and the vehicle was experiencing slipping during acceleration.
Diagnosis: After scanning with the GeekOBD APP, the P0878 code was retrieved. Visual inspection revealed a damaged transmission fluid pressure sensor.
Solution: Replaced the faulty transmission fluid pressure sensor and cleared the codes.
Cost: $250 (including $150 for the sensor and $100 for labor)
Result: The check engine light remained off, and the vehicle shifted smoothly again.
Case Study 2: GMC Terrain P0878 Diagnostic Case Study
Vehicle: 2016 GMC Terrain, 60,000 miles
Problem: Customer reported poor shifting and a check engine light.
Diagnosis: Using the GeekOBD APP, the P0878 code was confirmed. Further testing indicated damaged wiring in the sensor circuit.
Solution: Repaired the wiring and connections, and performed a transmission fluid flush.
Cost: $180 (including $80 for the fluid flush and $100 for repairs)
Result: The transmission performed well after repairs, with no further issues or codes.