Engine-CodesGeneric – B1231

B1231 Code - Open In The Evaporator Temperature Sensor Circuit

Quick Answer

The B1231 code indicates an open circuit in the evaporator temperature sensor circuit. Common causes include Faulty evaporator temperature sensor, Corrosion or damage to the sensor wiring, Loose or disconnected sensor connections. 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
B1231 indicates Open In The Evaporator Temperature Sensor Circuit.
Common causes
Common causes include Faulty evaporator temperature sensor, Corrosion or damage to the sensor wiring, Loose or disconnected sensor connections.
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 Aug 18, 2024
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Code B1231 Description

The B1231 code indicates an open circuit in the evaporator temperature sensor circuit. The evaporator temperature sensor is a component of the vehicle's HVAC system that helps regulate the temperature inside the car. When this sensor circuit is open, it means that the sensor is not able to send accurate temperature readings to the HVAC system, leading to potential issues with climate control and overall comfort inside the vehicle. This can result in erratic temperature changes, inefficient cooling or heating, and potentially even damage to other components of the HVAC system if not addressed promptly.

OBDII Code B1231 - Open In The Evaporator Temperature Sensor Circuit
B1231 Code - Open In The Evaporator Temperature Sensor Circuit

Common Causes of B1231

  1. Faulty evaporator temperature sensor
  2. Corrosion or damage to the sensor wiring
  3. Loose or disconnected sensor connections
  4. Electrical issues within the HVAC system
  5. Environmental factors such as moisture or debris affecting the sensor

Symptoms of B1231

  1. Inconsistent or inaccurate temperature control
  2. HVAC system blowing hot air when set to cold or vice versa
  3. HVAC system not responding to temperature adjustments
  4. Check Engine Light illuminated
  5. Reduced overall efficiency of the HVAC system

How to Fix B1231

  1. Begin by diagnosing the specific cause of the open circuit in the evaporator temperature sensor circuit using a diagnostic scanner.
  2. Inspect the sensor, wiring, and connections for any visible damage or corrosion.
  3. Replace the evaporator temperature sensor if it is found to be faulty.
  4. Repair or replace any damaged wiring or connectors.
  5. Clear the diagnostic trouble codes and test the HVAC system to ensure proper functionality.

Cost to Fix B1231

The cost of repairing an open circuit in the evaporator temperature sensor circuit can vary depending on the specific cause of the issue and the labor rates in your area. In general, you can expect to pay anywhere from $100 to $300 for parts and labor. Keep in mind that diagnostic time and labor rates can significantly impact the final cost, so it's advisable to get a few quotes from different auto repair shops to find the best price for your specific situation.

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Code B1231 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.

Frequently Asked Questions about B1231 Code

1. What are the common symptoms of OBDII code B1231 (Open In The Evaporator Temperature Sensor Circuit)?

- Common symptoms include inconsistent air conditioning performance, failure of the AC system to cool properly, and the AC compressor not engaging.

2. What are some possible causes of the B1231 code?

- Possible causes include a faulty evaporator temperature sensor, damaged wiring or connectors in the sensor circuit, or a problem with the AC control module.

3. How can I diagnose the issue causing the B1231 code?

- To diagnose the issue, you can use a multimeter to test the resistance of the evaporator temperature sensor, check for continuity in the sensor circuit, and inspect the wiring and connectors for any damage.

4. Can I repair the B1231 code issue myself?

- Depending on your skill level and access to tools, you may be able to repair the issue yourself by replacing the evaporator temperature sensor, repairing damaged wiring or connectors, or resetting the AC control module.

5. Is it safe to continue driving with the B1231 code present?

- It is generally not recommended to continue driving with the B1231 code present, as it can lead to further damage to the AC system and compromise your comfort while driving.

6. How much does it typically cost to repair the B1231 code?

- The cost of repairing the B1231 code can vary depending on the specific cause of the issue, but it may range from $100 to $300 for parts and labor.

7. Can the B1231 code be triggered by other issues unrelated to the evaporator temperature sensor?

- While the B1231 code is specifically related to an open circuit in the evaporator temperature sensor, other underlying issues in the AC system can potentially trigger this code as well.

8. Will resetting the OBDII system clear the B1231 code?

- Resetting the OBDII system may temporarily clear the B1231 code, but if the underlying issue is not addressed, the code is likely to reappear once the problem is detected again.

9. How important is it to address the B1231 code promptly?

- It is important to address the B1231 code promptly to ensure proper functioning of the AC system, maintain comfort while driving, and prevent potential damage to other components in the system.

10. Can a mechanic use a scan tool to diagnose the B1231 code?

- Yes, a mechanic can use a scan tool to read the B1231 code, retrieve additional diagnostic information, and help pinpoint the exact cause of the issue in the evaporator temperature sensor circuit.

Discuss the causes and fixes for B1231 OBDII Code

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