The P0871 code is a diagnostic trouble code (DTC) that indicates an issue with the Transmission Fluid Pressure Sensor/Switch ‘C’ Circuit Range/Performance. This code is triggered when the Transmission Control Module (TCM) detects that the input from the fluid pressure sensor does not align with expected values, suggesting a malfunction in the transmission’s pressure regulation system. Understanding this code is crucial for vehicle owners and DIY mechanics, as it can lead to severe transmission issues if not addressed promptly.
| P0871 Code Meaning | P0871 Code Common Causes |
|---|---|
| Transmission Fluid Pressure Sensor/Switch ‘C’ Circuit Range/Performance | Low transmission fluid levels |
| Incorrect voltage signal from the sensor | Faulty transmission high-pressure pump |
| Malfunctioning Transmission Control Module (TCM) | Wiring issues or corrosion in the sensor circuit |
| Internal transmission mechanical failures | Faulty transmission temperature sensor |
| Overheated transmission fluid | Clogged or dirty transmission filter |
Symptoms of P0871 Code
When the P0871 code is triggered, several symptoms may manifest, indicating potential problems with the transmission system:
- Check Engine Light: The most immediate symptom is the illumination of the check engine light on the dashboard.
- Transmission Slipping: Drivers may experience slipping during gear shifts, where the engine revs but the vehicle does not accelerate as expected.
- Rough Shifting: Shifts may become harsh or erratic, causing discomfort during driving.
- Increased Fuel Consumption: A malfunctioning transmission can lead to decreased fuel efficiency due to improper gear engagement.
- Burning Smell: An overheated transmission may emit a burning odor, often resembling burnt oil.
Technical Explanation of P0871 Code
The P0871 code relates to the operation of the Transmission Fluid Pressure Sensor, which monitors fluid pressure within the transmission. The TCM uses this data to manage shifting and ensure optimal performance. If the sensor reports values outside of its normal operating range—due to low fluid levels, electrical issues, or internal mechanical failures—the TCM triggers the P0871 code.
The “C” in the code refers specifically to one of several sensors that monitor fluid pressure. When this sensor fails or provides incorrect readings, it can lead to improper shifting and increased wear on transmission components.
Step-by-Step Diagnosis of P0871 Code
Diagnosing a P0871 code involves several steps to ensure accurate identification of the underlying issue:
1. Initial Scan and Code Retrieval
- Use an OBD-II scanner to retrieve trouble codes.
- Note any additional codes that may indicate related issues.
2. Visual Inspection
- Check for any visible signs of damage or corrosion in wiring and connectors associated with the Transmission Fluid Pressure Sensor.
- Inspect for fluid leaks around the transmission area.
3. Fluid Level Check
- Verify that the transmission fluid is at the proper level; low fluid can trigger this code.
- Inspect fluid condition; contaminated or burnt fluid should be replaced.
4. Electrical Testing
- Using a multimeter, check voltage readings at the Transmission Fluid Pressure Sensor.
- Ensure that voltage matches manufacturer specifications when the ignition is on but before starting the engine.
5. Sensor Functionality Test
- Disconnect the sensor and test its resistance using a multimeter.
- Compare readings against specifications provided in service manuals.
6. Further Component Testing
- If necessary, test related components such as the TCM and high-pressure pump for faults.
7. Road Test
- After repairs or adjustments, clear codes and take the vehicle for a test drive to see if the P0871 code reappears.
Solution Methods for P0871 Code
Addressing a P0871 code typically involves several potential solutions based on identified issues:
Low Transmission Fluid Levels
- Symptoms: Check engine light, slipping gears.
- Solution: Refill transmission fluid to manufacturer specifications. Ensure no leaks are present.
Faulty Transmission Fluid Pressure Sensor
- Symptoms: Erratic shifting, burning smell.
- Solution: Replace the faulty sensor. Ensure proper installation and connection.
Wiring Issues
- Symptoms: Intermittent check engine light.
- Solution: Repair or replace damaged wiring and connectors. Use dielectric grease to prevent future corrosion.
Malfunctioning TCM
- Symptoms: Persistent error codes after replacing other components.
- Solution: Reprogram or replace TCM as necessary. This often requires professional assistance due to complexity.
High-pressure Pump Failure
- Symptoms: Overheating transmission, poor shift quality.
- Solution: Inspect and replace high-pressure pump if found defective.
Clogged Transmission Filter
- Symptoms: Rough shifts, low power during acceleration.
- Solution: Replace clogged filter and flush transmission fluid as needed.
Cost Estimates for Repairs
The cost of repairs associated with a P0871 code can vary significantly based on diagnosis:
- Transmission Fluid Change: $100 – $250
- Transmission Fluid Pressure Sensor Replacement: $150 – $300
- Wiring Repairs: $50 – $200 depending on damage extent
- Transmission Control Module Replacement/Programming: $500 – $1500
- High-pressure Pump Replacement: $300 – $800
Warnings and Recommendations
When dealing with a P0871 trouble code, it’s essential to act swiftly:
- Ignoring this code can lead to severe transmission damage and costly repairs down the line.
- Always consult your vehicle’s service manual for specific diagnostic procedures and specifications.
- If unsure about any step in diagnosis or repair, seek professional assistance from a certified mechanic.
Closing Paragraph
The P0871 trouble code serves as an important indicator of potential issues within your vehicle’s transmission system. By understanding its meaning, symptoms, and proper diagnostic procedures, vehicle owners and DIY mechanics can take proactive steps toward resolution. Timely intervention not only prevents further damage but also ensures safe and efficient vehicle operation. Always remember that while some repairs can be handled independently, others may require professional expertise to guarantee optimal results.
Frequently Asked Questions About P0871
- What does P0871 indicate?
The P0871 code indicates a problem with the Transmission Fluid Pressure Sensor/Switch ‘C’ Circuit Range/Performance. - Can I drive my car with a P0871 code?
While it may be possible to drive short distances, it is not advisable as it can lead to further damage to your transmission. - How do I reset a P0871 code?
You can reset a P0871 code using an OBD-II scanner after addressing any underlying issues. - What are common fixes for a P0871 code?
Common fixes include replacing low fluid levels, faulty sensors, repairing wiring issues, or replacing malfunctioning components like pumps or control modules. - Is it safe to ignore a P0871 code?
No, ignoring this code can lead to significant transmission problems that may require expensive repairs. - How much does it cost to fix a P0871 code?
The cost can range from $100 for fluid changes up to $1500 for control module replacements depending on what needs fixing. - Can I diagnose this issue myself?
Yes, you can perform initial diagnostics using an OBD-II scanner and visual inspections; however, complex issues should be handled by professionals. - What vehicles commonly experience P0871 codes?
This issue can occur in various vehicles equipped with automatic transmissions but is particularly noted in certain Dodge/Chrysler models.