What Does B0338 Mean?
B0338 indicates the Body Control Module (BCM) or climate control module has detected an open circuit in the inside air temperature sensor. This sensor monitors cabin temperature to help the automatic climate control system regulate heating and cooling output. An open circuit means the electrical path is broken, preventing the module from receiving temperature data from the sensor.
Common Causes
45%
Failed inside air temperature sensor with internal open circuit
30%
Broken or disconnected wiring harness or connector at the sensor
15%
Corroded or damaged sensor connector pins causing poor contact
10%
Failed climate control module or BCM internal circuit fault
Diagnostic Steps
1
Step 1: Locate the inside air temperature sensor (typically mounted in the dashboard near the instrument cluster or center console) and visually inspect the sensor, connector, and wiring for obvious damage, disconnection, or corrosion
2
Step 2: Disconnect the sensor connector and use a digital multimeter to measure the resistance across the sensor terminals; typical thermistor sensors should read between 2-5k ohms at room temperature (refer to manufacturer specs); infinite resistance indicates a failed sensor
3
Step 3: With the sensor disconnected, check for continuity in the wiring harness from the sensor connector back to the climate control module or BCM using a multimeter; lack of continuity indicates a broken wire
4
Step 4: Inspect the sensor connector terminals for corrosion, bent pins, or damage; clean with electrical contact cleaner and check for proper pin tension; repair or replace connector if damaged
5
Step 5: If sensor, wiring, and connector test good, substitute a known-good sensor or use a resistor of appropriate value to simulate sensor operation and verify the module can read the signal
6
Step 6: Clear the code, operate the climate control system through various modes, and verify the repair by confirming the code does not return and the system responds properly to cabin temperature changes
Estimated Repair Cost
$80 - $350
Parts + labor, varies by vehicle and location
B0338 indicates the Body Control Module (BCM) or climate control module has detected an open circuit in the inside air temperature sensor. This sensor monitors cabin temperature to help the automatic climate control system regulate heating and cooling output. An open circuit means the electrical pat...
The most common cause of B0338 (Inside Air Temperature Sensor Open) is: Failed inside air temperature sensor with internal open circuit
Typical repair costs for B0338 range from $80 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or drivability and the vehicle can be driven normally. The automatic climate control system may not regulate temperature effectively, defaulting to manual operation or fixed output settings until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B0338 to identify the root cause.
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Quick Info
Category
Body
System
Climate Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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