B2071 Code - Stop Light Control Relay Malfunction
Quick Answer
This Diagnostic Trouble Code (DTC) is stored when the master cylinder solenoid (Skid Control ECU) detects that the brake light relay is malfunctioning and transmits this to the seat belt control ECU via CAN communication. Common causes include Faulty Vehicle Stability Control System, Faulty Seat Belt Control ECU. 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
- B2071 indicates Stop Light Control Relay Malfunction.
- Common causes
- Common causes include Faulty Vehicle Stability Control System, Faulty Seat Belt Control ECU.
- 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 B2071 Description
What are the Possible Causes of the DTC B2071?
- Faulty Vehicle Stability Control System
- Faulty Seat Belt Control ECU
How to Fix the DTC B2071?
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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B2071 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.
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Information for Specific Makes
- B2071 Ford — Hazard Switch Signal Short To Ground
- B2071 Lexus — Stop Light Control Relay Malfunction
- B2071 Lincoln — Hazard Switch Signal Short To Ground
- B2071 Mercury — Hazard Switch Signal Short To Ground
- B2071 Scion — Stop Light Control Relay Malfunction
- B2071 Toyota — Stop Light Control Relay Malfunction
Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service
- Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
- Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
- Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
- Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.
Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
Frequently Asked Questions about B2071 Code
1. What does the OBDII code B2071 mean?
B2071 indicates a malfunction in the stop light control relay, which is responsible for controlling the brake lights when the brake pedal is pressed.
2. What are the common symptoms of the B2071 code?
Symptoms may include non-functional brake lights, brake lights staying on constantly, or a warning light on the dashboard.
3. What causes the B2071 code to appear?
Common causes include a faulty stop light control relay, damaged wiring or connectors, or issues with the brake light switch.
4. Can a faulty brake light switch trigger the B2071 code?
Yes, a malfunctioning brake light switch can cause the stop light control relay to operate improperly, triggering the code.
5. How can I diagnose the B2071 code?
Diagnose by inspecting the stop light control relay, brake light switch, and related wiring for damage, corrosion, or loose connections. Testing the relay's functionality with a multimeter can also help.
6. Can I drive with the B2071 code present?
It’s not recommended since malfunctioning brake lights can create safety risks for you and other drivers.
7. How do I fix the B2071 code?
Repairs typically involve replacing the faulty stop light control relay, repairing damaged wiring, or replacing the brake light switch if necessary.
8. How much does it cost to fix the B2071 code?
The repair cost varies but typically ranges from $50 to $150 for parts and labor, depending on the vehicle and the specific issue.
9. Can a blown fuse cause the B2071 code?
Yes, a blown fuse in the brake light circuit can disrupt the stop light relay’s function and trigger the code.
10. How can I prevent the B2071 code from recurring?
Regularly inspect and maintain the brake light system, including the relay, wiring, and brake light switch, to prevent wear and corrosion.
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