AutoCodes – Generic – B1256

B1256 Code - Air Temperature External Sensor Circuit Short To Battery

Quick Answer

The Powertrain Control Module (PCM) monitors the Air Temperature External Sensor. Common causes include Faulty Air Temperature External Sensor, Air Temperature External Sensor harness is open or shorted, Air Temperature External Sensor circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: B1256 indicates Air Temperature External Sensor Circuit Short To Battery.
Common causes: Common causes include Faulty Air Temperature External Sensor, Air Temperature External Sensor harness is open or shorted, Air Temperature External Sensor circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 22,928

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1256 Description

The Powertrain Control Module (PCM) monitors the Air Temperature External Sensor. The PCM sets the OBDII code when the Air Temperature External Sensor is not to factory specifications.

OBDII Code B1256 - Air Temperature External Sensor Circuit Short To Battery - AutoCodes.com — B1256 Code - Air Temperature External Sensor Circuit Short To Battery

What does this mean?

What are the Possible Causes of the DTC B1256?

Faulty Air Temperature External Sensor
Air Temperature External Sensor harness is open or shorted
Air Temperature External Sensor circuit poor electrical connection

How to Fix the DTC B1256?

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 B1256 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 B1256 code?

Need more information on how to fix the B1256 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1256 code diagnosed by a professional: Find a repair shop in your area

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 B1256 Code

1. What are the common symptoms of OBDII code B1256?

- Common symptoms include incorrect temperature readings on the vehicle's display, issues with the heating or cooling system, and potential illumination of the check engine light.

2. What does the OBDII code B1256, Air Temperature External Sensor Circuit Short To Battery, indicate?

- This code indicates that there is a short circuit between the air temperature sensor and the battery in the vehicle's external sensor circuit.

3. What are the possible causes of OBDII code B1256?

- Possible causes include damaged wiring or connectors in the air temperature sensor circuit, a faulty air temperature sensor, or a malfunctioning control module.

4. How can I diagnose the cause of OBDII code B1256?

- Diagnosing the issue involves visually inspecting the wiring and connectors, testing the air temperature sensor for proper operation, and using a multimeter to check for continuity and shorts in the circuit.

5. Can I repair OBDII code B1256 myself?

- Depending on your skill level and access to tools, you may be able to repair this code yourself by replacing damaged wiring, connectors, or the air temperature sensor. However, seeking professional help is recommended for accurate diagnosis and repair.

6. Is it safe to drive with OBDII code B1256 present?

- It is generally not recommended to drive with this code present, as it can lead to inaccurate temperature readings and potential issues with the vehicle's heating or cooling systems.

7. How much does it typically cost to repair OBDII code B1256?

- The cost of repairing this code can vary depending on the extent of the damage and the specific components that need to be replaced. It is advisable to consult a mechanic for an accurate estimate.

8. Can extreme weather conditions cause OBDII code B1256 to trigger?

- Extreme weather conditions can potentially affect the air temperature sensor and its circuit, leading to the triggering of OBDII code B1256. It's important to keep the sensor and its wiring protected from harsh elements.

9. Will resetting the OBDII system clear code B1256?

- Resetting the OBDII system may temporarily clear the code, but if the underlying issue causing code B1256 is not addressed, the code is likely to reappear. It's important to diagnose and repair the root cause of the problem.

10. How often should I check the air temperature sensor and its circuit for issues to prevent OBDII code B1256?

- It is recommended to include visual checks of the air temperature sensor and its circuit as part of regular vehicle maintenance to catch any potential issues early and prevent the triggering of OBDII code B1256.