Quick Answer
P0787 means: The P0787 code indicates a low voltage signal from the transmission fluid pressure sensor, affecting gear shifting.
Can I drive with P0787? Immediate attention is recommended to prevent further transmission damage.
Common Questions
What does P0787 mean and how does it affect my car?
The P0787 code indicates a low reading from the transmission fluid pressure sensor, which can lead to poor shifting performance and potential transmission damage. If ignored, it may cause your car to hesitate or slip gears, making it unsafe to drive.
What are the most common causes of P0787 and how much does it cost to fix?
Common causes of P0787 include a faulty fluid pressure sensor, wiring issues, and low transmission fluid. Repair costs can range from $100 to $300, depending on the specific issue and labor costs.
Can I drive my car with P0787 or should I stop immediately?
It’s advisable to stop driving your vehicle immediately if you see the P0787 code. Continuing to drive can lead to severe transmission damage, resulting in much higher repair costs.
How can I diagnose P0787 myself using GeekOBD APP?
To diagnose P0787 using the GeekOBD APP, connect the app to your vehicle’s OBD2 port, run a full scan to retrieve diagnostic codes, and examine the freeze frame data for additional context like engine speed and load.
What vehicles are most commonly affected by P0787?
Vehicles like the 2008-2015 Honda Accord and 2010-2015 Ford Fusion frequently encounter the P0787 code, often due to their transmission design and sensor placement.
How can I prevent P0787 from happening again?
Regular maintenance, including checking transmission fluid levels and replacing the fluid as recommended, can help prevent the recurrence of P0787. Additionally, ensure that all wiring and connections are in good condition.
What is P0787?
The P0787 diagnostic trouble code indicates an issue with the transmission fluid pressure sensor circuit, specifically that the signal is lower than expected. This code typically arises when the Engine Control Module (ECM) detects an abnormal low voltage reading from the transmission fluid pressure sensor, which is crucial for regulating the transmission’s shifting patterns. In simpler terms, if your vehicle is throwing this code, it may be experiencing problems with shifting gears smoothly or could even lead to complete transmission failure if not addressed promptly. The transmission fluid pressure sensor monitors fluid pressure inside the transmission and sends this information to the ECM, which adjusts the transmission’s operation accordingly. Ignoring this code can result in severe driveability issues, including slipping gears and unexpected acceleration or deceleration, which can pose safety risks. If you own a 2008-2015 Honda Accord or a 2010-2015 Ford Fusion, it's crucial to be aware of this code and its implications, as these models are often reported with this issue. Addressing it early can save you from costly repairs down the line.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P0787 is present:
- Check engine light stays on constantly, indicating an issue that needs to be diagnosed.
- Engine hesitates during acceleration, which can be frustrating and affect overall driveability.
- Fuel economy decreased by 10-15%, noticeable in your monthly fuel expenses.
- Transmission slips or unexpectedly changes gears, creating a jarring driving experience.
- Unusual noises from the transmission, like grinding or whining, which could signify internal damage.
Possible Causes
Most common causes of P0787 (ordered by frequency):
- Faulty transmission fluid pressure sensor (40% likelihood) - This is the most common cause, where the sensor fails to provide accurate readings due to wear or damage.
- Wiring issues (30% likelihood) - Damaged wiring or loose connections in the sensor circuit can lead to poor electrical signals.
- Low transmission fluid (15% likelihood) - Insufficient fluid levels can cause pressure issues, leading to incorrect sensor readings.
- Transmission control module failure (10% likelihood) - A malfunctioning TCM may misinterpret the signals from the pressure sensor.
- Rare mechanical failure (5% likelihood) - Internal transmission issues, such as a damaged pump or valve body, can cause pressure inconsistencies.
P0787 Repair Costs
Cost Breakdown by Repair Type
Sensor Replacement
Replacing the faulty transmission fluid pressure sensor.
- Total: $150 - $300
- Success rate: 85%
Wiring Repair
Repairing damaged wiring or connections in the sensor circuit.
- Total: $100 - $200
- Success rate: 70%
Money-Saving Tips for P0787
- 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 P0787 Diagnosis Process
Follow these systematic steps to accurately diagnose P0787. 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).
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).
Step 3: Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the transmission fluid pressure sensor (20-30 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the transmission fluid pressure sensor (20-30 minutes).
Step 4: Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes)
Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes).
Step 5: Step 5: Road test verification - Drive vehicle under various conditions to confirm repair success (15-20 minutes)
Step 5: Road test verification - Drive vehicle under various conditions to confirm repair success (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: Transmission Sensor Replacement on 2011 Honda Accord
Vehicle: 2011 Honda Accord, 85,000 miles
Problem: Customer reported check engine light and rough shifting.
Diagnosis: Scanned for codes, found P0787; visual inspection revealed a faulty sensor.
Solution: Replaced the transmission fluid pressure sensor and refilled transmission fluid.
Cost: $250 (sensor $150, labor $100)
Result: Restored smooth shifting and cleared check engine light.
Case Study 2: Wiring Repair for 2013 Ford Fusion
Vehicle: 2013 Ford Fusion, 60,000 miles
Problem: Check engine light and slipping transmission.
Diagnosis: Diagnosed with P0787; found damaged wiring in the sensor circuit.
Solution: Repaired wiring and reconnected the sensor.
Cost: $180 (wiring repair $80, labor $100)
Result: Resolved slipping issue and no more warning lights.