AutoCodes – Generic – B0338

B0338 Code - Inside Air Temperature Sensor Open

Quick Answer

The ambient air temperature sensor allows the Heating, Ventilation, and Air Conditioning (HVAC) Control Module to monitor the temperature of the air surrounding the front of the vehicle. Common causes include Faulty Inside Temperature Sensor, Inside Temperature Sensor harness is open or shorted, Inside Temperature Sensor 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: B0338 indicates Inside Air Temperature Sensor Open.
Common causes: Common causes include Faulty Inside Temperature Sensor, Inside Temperature Sensor harness is open or shorted, Inside Temperature Sensor 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 1,771

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 11, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0338 Description

The ambient air temperature sensor allows the Heating, Ventilation, and Air Conditioning (HVAC) Control Module to monitor the temperature of the air surrounding the front of the vehicle. The inside air temperature sensor allows the HVAC control module to monitor the temperature of the air inside the passenger compartment. 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 circuits. The HVAC control module monitors the voltage drops across the air temperature sensors and uses the inputs for automatic control calculations. The HVAC control module also uses the ambient air temperature input to calculate the value of the ambient air temperature display. When the air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the air temperatures are hot, the resistances of the sensors are low and the voltage signals are low.

OBDII Code B0338 - Inside Air Temperature Sensor Open - AutoCodes.com — B0338 Code - Inside Air Temperature Sensor Open

What does this mean?

What are the Possible Causes of the DTC B0338?

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

How to Fix the DTC B0338?

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 B0338 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 B0338 code?

Need more information on how to fix the B0338 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B0338 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B0338 Buick — Inside Air Temperature Sensor Open
B0338 Cadillac — Inside Air Temperature Sensor Open
B0338 Chevrolet — Inside Air Temperature Sensor Open
B0338 GMC — Inside Air Temperature Sensor Open

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 B0338 Code

1. What are the common symptoms of OBDII code B0338 (Inside Air Temperature Sensor Open)?

The common symptoms include inaccurate readings on the vehicle's climate control system, such as incorrect temperature display or erratic behavior of the HVAC system.

2. What does the OBDII code B0338 indicate?

OBDII code B0338 indicates that there is an open circuit in the inside air temperature sensor circuit, resulting in a malfunction in the sensor's operation.

3. What are the potential causes of OBDII code B0338?

The potential causes include a faulty inside air temperature sensor, damaged wiring or connectors in the sensor circuit, or a problem with the HVAC control module.

4. How can I diagnose the cause of OBDII code B0338?

Diagnosing the cause involves inspecting the inside air temperature sensor, checking the wiring and connectors for any damage or loose connections, and using a multimeter to test the sensor's resistance.

5. How can I repair OBDII code B0338?

To repair OBDII code B0338, you may need to replace the inside air temperature sensor if it is faulty, repair any damaged wiring or connectors in the circuit, or reset the HVAC control module after fixing the issue.

6. Can I drive my vehicle with OBDII code B0338?

It is generally safe to drive the vehicle with this code, but it is recommended to address the issue promptly to ensure proper operation of the climate control system.

7. Will OBDII code B0338 cause any other problems in my vehicle?

While the code itself may not cause immediate drivability issues, it can affect the accuracy of the climate control system and potentially impact the overall comfort inside the vehicle.

8. How do I reset OBDII code B0338?

You can reset OBDII code B0338 using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes. However, it is important to address the underlying issue causing the code before resetting it.

9. Is OBDII code B0338 a common issue in certain vehicle makes and models?

OBDII code B0338 may be more common in specific vehicle makes and models that are equipped with an inside air temperature sensor as part of their climate control system.

10. How can I prevent OBDII code B0338 from occurring in the future?

To prevent OBDII code B0338, it is important to perform regular maintenance checks on the vehicle's climate control system, including inspecting the inside air temperature sensor and its wiring for any signs of wear or damage.