AutoCodes – Chevrolet – B0178 Chevrolet

B0178 Chevrolet Code - Output Air Temperature Sensor 2 Circuit

Quick Answer

Air temperature sensors allow the Heating, Ventilation, and Air Conditioning (HVAC) Control Module to monitor the temperature of the discharge air in the HVAC ducts. Common causes include Faulty Output Air Temperature Sensor 2, Output Air Temperature Sensor 2 harness is open or shorted, Output Air Temperature Sensor 2 circuit poor electrical connection. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: B0178 Chevrolet indicates Output Air Temperature Sensor 2 Circuit.
Common causes: Common causes include Faulty Output Air Temperature Sensor 2, Output Air Temperature Sensor 2 harness is open or shorted, Output Air Temperature Sensor 2 circuit poor electrical connection.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 6,463

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 10, 2021

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B0178 Chevrolet Description

Air temperature sensors allow the Heating, Ventilation, and Air Conditioning (HVAC) Control Module to monitor the temperature of the discharge air in the HVAC ducts. The module applies 5 volts to internal input resistors that are connected to the signal circuits of the air temperature sensors. The module provides ground to the air temperature sensors through the low reference circuit. The HVAC control module monitors the voltage drops across the air temperature sensors and uses the inputs for automatic control calculations. When the duct air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the duct air temperatures are hot, the resistances of the sensors are low and the voltage signals are low. The HVAC control module converts the voltage values to count values where 1 volt is approximately equal to 51 counts.

OBDII Code B0178 Chevrolet - Output Air Temperature Sensor 2 Circuit - AutoCodes.com — B0178 Chevrolet Code - Output Air Temperature Sensor 2 Circuit

What does this mean?

What are the Possible Causes of the DTC B0178 Chevrolet?

Faulty Output Air Temperature Sensor 2
Output Air Temperature Sensor 2 harness is open or shorted
Output Air Temperature Sensor 2 circuit poor electrical connection
Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module

How to Fix the DTC B0178 Chevrolet?

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 does this mean?

Code Tech Notes

B0178 05: Output Air Temperature Sensor 2 Circuit Short to Battery or Open
B0178 02: Output Air Temperature Sensor 2 Circuit Short to Ground

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B0178 Chevrolet 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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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 B0178 Chevrolet Code

1. What are common symptoms of OBDII code B0178 in a Chevrolet related to the Output Air Temperature Sensor 2 Circuit?

- Common symptoms include issues with the heating, ventilation, and air conditioning (HVAC) system, such as inconsistent temperature control or lack of response to temperature adjustments.

2. What can cause OBDII code B0178 to trigger in a Chevrolet?

- The code B0178 may be triggered by a faulty output air temperature sensor, damaged wiring or connectors, or a malfunction in the HVAC control module.

3. How can I diagnose the Output Air Temperature Sensor 2 Circuit issue in my Chevrolet?

- Diagnosing the issue involves using an OBDII scanner to retrieve the specific code, checking the sensor's wiring and connectors for damage, and testing the sensor's resistance and functionality.

4. Can I continue driving my Chevrolet with OBDII code B0178 present?

- It is generally safe to drive with this code, but it is recommended to address the issue promptly to ensure proper functioning of the HVAC system and avoid potential discomfort.

5. What are some repair tips for fixing OBDII code B0178 in a Chevrolet?

- Repair tips include checking and replacing the output air temperature sensor if faulty, repairing any damaged wiring or connectors, and resetting the trouble code after completing the repairs.

6. Is it possible to reset the OBDII code B0178 in a Chevrolet without fixing the underlying issue?

- While you can clear the code temporarily, it is crucial to address the root cause to prevent the code from reappearing and ensure the proper operation of the HVAC system.

7. How much does it typically cost to repair OBDII code B0178 related to the Output Air Temperature Sensor 2 Circuit in a Chevrolet?

- The cost of repairs can vary depending on the specific issue, but it may involve replacing the sensor, repairing wiring, or addressing problems with the HVAC control module. Costs can range from $50 to $300 or more.

8. Are there any common DIY solutions for fixing OBDII code B0178 in a Chevrolet?

- DIY solutions may include checking and cleaning sensor connectors, inspecting wiring for damage, and replacing the sensor if necessary. However, more complex issues may require professional diagnosis and repair.

9. How long does it typically take to repair OBDII code B0178 in a Chevrolet?

- The repair time can vary based on the extent of the issue and the specific repairs needed. In general, fixing the Output Air Temperature Sensor 2 Circuit problem can take anywhere from 1 to 3 hours.

10. Can a faulty Output Air Temperature Sensor 2 Circuit impact the overall performance of my Chevrolet?

- While the impact on performance may be minimal, a faulty sensor can affect the HVAC system's ability to regulate cabin temperature effectively, leading to discomfort for passengers. Addressing the issue promptly is recommended.