Engine-CodesGeneric – P0871

P0871 Code - OD Pressure Switch Rationality Fault

Quick Answer

The P0871 diagnostic trouble code (DTC) refers to an OD (overdrive) pressure switch rationality fault in the vehicle's transmission system. Common causes include Faulty overdrive pressure switch, Wiring or connector issues, Low transmission fluid levels. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0871 indicates OD Pressure Switch Rationality Fault.
Common causes
Common causes include Faulty overdrive pressure switch, Wiring or connector issues, Low transmission fluid levels.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code P0871 Description

The P0871 diagnostic trouble code (DTC) refers to an OD (overdrive) pressure switch rationality fault in the vehicle's transmission system. This code indicates that there is an issue with the operation of the overdrive pressure switch, which is responsible for regulating the hydraulic pressure in the transmission. The overdrive function allows the vehicle to achieve better fuel efficiency at higher speeds by reducing engine RPMs.

OBDII Code P0871 - OD Pressure Switch Rationality Fault
P0871 Code - OD Pressure Switch Rationality Fault

Common Causes of P0871

  1. Faulty overdrive pressure switch
  2. Wiring or connector issues
  3. Low transmission fluid levels
  4. Internal transmission damage
  5. Electronic control module (ECM) malfunction

Symptoms of P0871

  1. Harsh or delayed shifting
  2. Slipping gears
  3. Overdrive not engaging
  4. Transmission overheating
  5. Illumination of the Check Engine Light

How to Fix P0871

  1. Begin by conducting a thorough diagnosis using a scan tool to retrieve the specific trouble code and identify the root cause of the issue.
  2. Inspect the wiring and connectors associated with the overdrive pressure switch for any signs of damage or corrosion. Repair or replace as needed.
  3. Check the transmission fluid level and condition. Top off or replace the fluid if necessary.
  4. Test the overdrive pressure switch and replace it if it is found to be faulty.
  5. Clear the DTC and test drive the vehicle to ensure that the issue has been resolved.

Cost to Fix P0871

The cost of repairing a P0871 code can vary depending on the extent of the issue and the specific repairs needed. Generally, the replacement of the overdrive pressure switch and associated components can range from $150 to $300. Additional costs may include diagnostic fees, fluid replacement, and labor charges. It is advisable to consult with a qualified mechanic or transmission specialist for an accurate cost estimate based on your vehicle's make and model. Keep in mind that labor rates and part prices can fluctuate based on location and service provider.

When is the Code Detected?

This code is set if the OD pressure switch is open or closed at the wrong time in a given gear

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Code P0871 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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