B2871 Code - Left Rear Tire Pressure Sensor Fault
Quick Answer
The Tire Pressure Monitor (TPM) system monitors the air pressure in the 4 road tires with wheel-mounted tire pressure sensors. Common causes include Low tire pressure, Tire pressure sensor is missing or damaged, Spare tire is installed as a road wheel. 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
- B2871 indicates Left Rear Tire Pressure Sensor Fault.
- Common causes
- Common causes include Low tire pressure, Tire pressure sensor is missing or damaged, Spare tire is installed as a road wheel.
- 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.
Code B2871 Description
Each tire pressure sensor transmission is compared against a low-pressure limit (pressure listed on vehicle certification label minus 25 percent, which will be about 6-9 psi). If it is determined that the tire pressure has fallen below this limit, the SJB sends a message to the instrument cluster, which then illuminates the low pressure warning indicator and displays the appropriate message(s) in the message center (if equipped).
What are the Possible Causes of the DTC B2871?
- Low tire pressure
- Tire pressure sensor is missing or damaged
- Spare tire is installed as a road wheel
- Incorrect tire pressure sensor is installed
- Tire pressure sensor installed incorrectly
- Faulty Left Rear Tire Pressure Sensor
How to Fix the DTC B2871?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B2871 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the B2871 code?
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Need Help with the Code?
Get the B2871 code diagnosed by a professional: Find a repair shop in your area
Information for Specific Makes
- B2871 Ford — Left Rear Tire Pressure Sensor Fault
- B2871 Lincoln — Left Rear Tire Pressure Sensor Fault
- B2871 Mercury — Left Rear Tire Pressure Sensor Fault
Frequently Asked Questions about B2871 Code
1. What does the OBDII code B2871 mean?
The code B2871 indicates a fault with the left rear tire pressure sensor, often related to a malfunction, communication issue, or low battery in the sensor.
2. What are the common symptoms of a B2871 code?
Symptoms may include a tire pressure warning light on the dashboard, inaccurate tire pressure readings, or no data displayed for the left rear tire.
3. What causes the B2871 code to appear?
Common causes include a faulty tire pressure sensor, a weak or dead sensor battery, damaged wiring, or interference with the sensor signal.
4. Can I drive with a B2871 code?
Yes, you can drive, but it’s important to manually check your tire pressure to ensure safety, as the left rear tire pressure sensor may not provide accurate readings.
5. How is the B2871 code diagnosed?
A technician will use a scan tool to confirm the code, inspect the left rear tire pressure sensor, check for sensor signal strength, and examine the wiring and connections.
6. How do you fix a B2871 code?
Repairs may involve replacing the faulty left rear tire pressure sensor, reprogramming the sensor, or repairing any damaged wiring or connections.
7. How much does it cost to fix a B2871 code?
The cost varies, but replacing a tire pressure sensor typically ranges from $50 to $150 for the part, plus labor costs.
8. Can a low battery in the tire pressure sensor cause a B2871 code?
Yes, a weak or dead sensor battery is a common cause of this code and may require sensor replacement.
9. Do I need to reprogram the sensor after replacing it?
Yes, most tire pressure sensors require reprogramming or relearning using a scan tool to ensure proper communication with the vehicle.
10. Could extreme weather trigger a B2871 code?
Yes, extreme cold or heat can sometimes affect sensor functionality or battery performance, potentially triggering this code.
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