AutoCodes – Generic – B2456

B2456 Code - Auxiliary Heater Coolant Sensor Circuit Short to Ground

Quick Answer

The Powertrain Control Module (PCM) monitors the Auxiliary Heater Coolant Sensor. Common causes include Faulty Auxiliary Heater Coolant Sensor, Auxiliary Heater Coolant Sensor harness is open or shorted, Auxiliary Heater Coolant Sensor 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: B2456 indicates Auxiliary Heater Coolant Sensor Circuit Short to Ground.
Common causes: Common causes include Faulty Auxiliary Heater Coolant Sensor, Auxiliary Heater Coolant Sensor harness is open or shorted, Auxiliary Heater Coolant Sensor 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.

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Code Popularity 4,818

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Dec 08, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2456 Description

The Powertrain Control Module (PCM) monitors the Auxiliary Heater Coolant Sensor. The PCM sets the OBDII code when the Auxiliary Heater Coolant Sensor is not to factory specifications.

OBDII Code B2456 - Auxiliary Heater Coolant Sensor Circuit Short to Ground - AutoCodes.com — B2456 Code - Auxiliary Heater Coolant Sensor Circuit Short to Ground

What does this mean?

What are the Possible Causes of the DTC B2456?

Faulty Auxiliary Heater Coolant Sensor
Auxiliary Heater Coolant Sensor harness is open or shorted
Auxiliary Heater Coolant Sensor circuit poor electrical connection

How to Fix the DTC B2456?

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 B2456 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 B2456 code?

Need more information on how to fix the B2456 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B2456 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 B2456 Code

1. What are the common symptoms of OBDII code B2456?

Symptoms may include the heater not working properly, reduced cabin heating, or a check engine light illuminated on the dashboard.

2. What causes the OBDII code B2456 to trigger?

This code is triggered when the auxiliary heater coolant sensor circuit detects a short to ground, indicating a problem with the sensor or the wiring.

3. How can I diagnose the issue causing OBDII code B2456?

A thorough inspection of the auxiliary heater coolant sensor and its wiring is recommended. Testing the sensor for proper function and checking the wiring for any visible damage or shorts can help pinpoint the issue.

4. Can I still drive my vehicle with OBDII code B2456?

It is not recommended to drive the vehicle with this code present, as it can lead to further issues with the auxiliary heater system and potentially affect the overall performance of the vehicle.

5. How can I repair OBDII code B2456?

Repairing this code typically involves replacing the faulty auxiliary heater coolant sensor or repairing the damaged wiring causing the short to ground. It is advisable to consult a professional mechanic for proper diagnosis and repair.

6. Are there any DIY tips for fixing OBDII code B2456?

DIY tips may include checking the sensor connection for corrosion, ensuring proper grounding of the sensor, and inspecting the wiring for any visible damage before attempting any repairs.

7. Will resetting the OBDII code B2456 make it go away permanently?

Resetting the code may temporarily clear the check engine light, but if the underlying issue causing the code is not addressed, it is likely to reappear. It is crucial to diagnose and repair the root cause of the problem.

8. Is OBDII code B2456 a serious issue?

While it may not directly affect the drivability of the vehicle, OBDII code B2456 should be addressed promptly to prevent any further damage to the auxiliary heater system and ensure proper functioning of the vehicle.

9. Can extreme weather conditions trigger OBDII code B2456?

Extreme cold temperatures can potentially exacerbate issues with the auxiliary heater coolant sensor circuit, leading to the triggering of OBDII code B2456. Proper maintenance and care during such conditions are advisable.

10. Is it necessary to replace the entire auxiliary heater system for OBDII code B2456?

In most cases, only the faulty auxiliary heater coolant sensor or damaged wiring needs to be repaired or replaced, rather than the entire auxiliary heater system. A thorough diagnosis will determine the extent of the repair needed.