B2957 Code - Blend Door Open Circuit Failure Or Short
Quick Answer
Under normal operation, to rotate the mode door actuator clockwise, the Electric Manual Temperature Control (EMTC) module or Electronic Automatic Temperature Control (EATC) module supplies voltage to the Blend, Floor/Defrost and Panel mode door actuator motors through the door actuator feed B circuits, and supplies ground through the door actuator feed A circuits. Common causes include Faulty Blend Door Actuator Motor, Blend Door Actuator Motor harness is open or shorted, Blend Door Actuator Motor circuit poor electrical connection. 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
- B2957 indicates Blend Door Open Circuit Failure Or Short.
- Common causes
- Common causes include Faulty Blend Door Actuator Motor, Blend Door Actuator Motor harness is open or shorted, Blend Door Actuator Motor circuit poor electrical connection.
- 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 B2957 Description
The mode door actuator feedback resistors are supplied a ground from the EMTC module or EATC module by the mode door actuator return circuits and a 5-volt reference voltage on the mode door actuator reference circuits. The EMTC module or EATC module reads the voltage on the mode door actuator feedback circuits to determine the mode door actuator position by the position of the actuator feedback resistor wiper arm.
What are the Possible Causes of the DTC B2957?
- Faulty Blend Door Actuator Motor
- Blend Door Actuator Motor harness is open or shorted
- Blend Door Actuator Motor circuit poor electrical connection
- Faulty Electric Manual Temperature Control (EMTC) Module or Electronic Automatic Temperature Control (EATC) Module
How to Fix the DTC B2957?
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 B2957 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 B2957 code?
Need more information on how to fix the B2957 code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the B2957 code diagnosed by a professional: Find a repair shop in your area
Information for Specific Makes
- B2957 Buick — Security System Sensor Data Circuit Low
- B2957 Cadillac — Security System Sensor Data Circuit Low
- B2957 Chevrolet — Security System Sensor Data Circuit Low
- B2957 Ford — Blend Door Open Circuit Failure Or Short
- B2957 GMC — Security System Sensor Data Circuit Low
- B2957 Lincoln — Blend Door Open Circuit Failure Or Short
- B2957 Mercury — Blend Door Open Circuit Failure Or Short
Frequently Asked Questions about B2957 Code
1. What does OBDII code B2957 mean?
B2957 indicates a Blend Door Open Circuit Failure or Short, meaning there's an electrical issue preventing the blend door actuator from functioning properly.
2. What are the symptoms of code B2957?
Common symptoms include inconsistent cabin temperature, inability to control airflow between vents, and unusual noises from the HVAC system.
3. What causes code B2957 to appear?
The code can be triggered by a faulty blend door actuator, damaged wiring or connectors, or a malfunctioning HVAC control module.
4. Can a blown fuse cause code B2957?
Yes, a blown HVAC-related fuse can interrupt power to the blend door actuator, potentially causing this code.
5. How do you diagnose code B2957?
Start by checking the blend door actuator for physical or electrical damage, inspecting wiring and connectors for shorts or open circuits, and testing the HVAC control module.
6. Can you drive with code B2957 present?
Yes, but you may experience discomfort due to an inability to control the cabin temperature or airflow properly.
7. How is code B2957 fixed?
Repairs may include replacing the blend door actuator, repairing or replacing damaged wiring, or reprogramming or replacing the HVAC control module.
8. How much does it cost to fix code B2957?
The cost can range from $150 to $500 depending on whether the blend door actuator or HVAC control module needs replacement.
9. Can you clear code B2957 without repairing it?
Clearing the code without addressing the root cause will likely result in the code returning as the issue persists.
10. Is code B2957 specific to any vehicle make or model?
No, code B2957 can occur in various vehicles equipped with an OBDII system and electronic blend door actuators.
Discuss the causes and fixes for B2957 OBDII Code
Code B2957 comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
