AutoCodes – Generic – B370A

B370A Code - Rain Sensor Internal Malfunction

Quick Answer

B+ and ground is supplied at all times to the rain sensor. Common causes include Faulty Windshield Outside Moisture Sensor (Rain Sensor), Windshield Outside Moisture Sensor harness is open or shorted, Windshield Outside Moisture 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: B370A indicates Rain Sensor Internal Malfunction.
Common causes: Common causes include Faulty Windshield Outside Moisture Sensor (Rain Sensor), Windshield Outside Moisture Sensor harness is open or shorted, Windshield Outside Moisture 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 5,802

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 Mar 13, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B370A Description

B+ and ground is supplied at all times to the rain sensor. The rain sensor communicates with the Body Control Module (BCM) via serial data. When the ignition is in the ON or ACCESSORY position and the windshield wiper/washer switch is in the intermittent delay position, the BCM monitors the rain sensor to determine the rain build up on the windshield. As rain builds up on the windshield, the BCM will command the wipers to activate. The sensitivity of the wiper frequency is controlled by the intermittent delay of the windshield wiper/washer switch. As the sensitivity is increased, the BCM will command more frequent wiper activation based on rain build up on the windshield.
The system supports the rain sensor On/Off button. The AUTO switch is located on the turn signal/multifunction switch. Press the auto button to turn the rain sensor On/Off. When rain sensor is turned on and the rain sensor wipe sensitivity positions is adjusted by the front delay switch. The wipers can be adjusted for more or less sensitivity to moisture. When rain sensor turned off, the wipers operate as timed intermittent wipers and can be adjusted for more or less frequent wipes.
If the ignition is in ON/RUN and the front band is in one of the sensitivity settings when auto is turned on or off, a message may display indicating if rain sensor was turned on or off.
If the ignition is in ON/RUN and the front band is not in one of the sensitivity settings when auto is turned on, a message may display indicating that the wiper band must be in one of the sensitivity settings for rain sensor to operate.
The Diagnostic Trouble Code (DTC) sets when communication between the BCM and the rain sensor is interrupted, and an interruption in communication is a serial data fault.

OBDII Code B370A - Rain Sensor Internal Malfunction - AutoCodes.com — B370A Code - Rain Sensor Internal Malfunction

What does this mean?

What are the Possible Causes of the DTC B370A?

Faulty Windshield Outside Moisture Sensor (Rain Sensor)
Windshield Outside Moisture Sensor harness is open or shorted
Windshield Outside Moisture Sensor circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B370A?

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 B370A 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 B370A code?

Need more information on how to fix the B370A code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B370A code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B370A Cadillac — Rain Sensor Internal Malfunction
B370A Chevrolet — Rain Sensor Internal Malfunction
B370A Saturn — Rain Sensor Internal Malfunction

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 B370A Code

1. What are the common symptoms of OBDII code B370A - Rain Sensor Internal Malfunction?

The common symptoms include the windshield wipers not functioning properly in response to rainfall, erratic wiper movement, or the wipers turning on unexpectedly.

2. What can cause the OBDII code B370A to trigger for Rain Sensor Internal Malfunction?

The code B370A can be triggered by issues such as a faulty rain sensor module, damaged wiring or connectors, or a malfunctioning windshield wiper control module.

3. How can I diagnose the cause of OBDII code B370A for Rain Sensor Internal Malfunction?

Diagnosing the issue typically involves checking the rain sensor module, inspecting the wiring and connectors for damage, and testing the windshield wiper control module for proper operation.

4. Is it safe to continue driving with OBDII code B370A - Rain Sensor Internal Malfunction?

While the vehicle may still be operable with this code, it is recommended to address the issue promptly to ensure proper functioning of the windshield wipers, especially in rainy conditions.

5. Can I repair OBDII code B370A - Rain Sensor Internal Malfunction myself?

Repairing this code may require some technical knowledge and specialized tools. It is recommended to consult a professional mechanic or refer to the vehicle's service manual for guidance.

6. How much does it typically cost to fix OBDII code B370A - Rain Sensor Internal Malfunction?

The cost of fixing this code can vary depending on the underlying cause of the issue. It is advisable to get a diagnostic assessment from a mechanic to determine the exact cost of repairs.

7. Are there any temporary fixes for OBDII code B370A - Rain Sensor Internal Malfunction?

Temporary fixes such as resetting the rain sensor system or checking and cleaning the sensor surface may help in some cases, but a permanent solution will likely require proper diagnosis and repair.

8. Can extreme weather conditions affect the triggering of OBDII code B370A for Rain Sensor Internal Malfunction?

Yes, extreme weather conditions like heavy rain or snow can sometimes exacerbate issues with the rain sensor system, leading to the triggering of the B370A code.

9. What role does the rain sensor play in the vehicle's overall safety system?

The rain sensor helps ensure visibility by automatically activating the windshield wipers when it detects moisture on the windshield, contributing to safer driving in adverse weather conditions.

10. How long does it typically take to repair OBDII code B370A - Rain Sensor Internal Malfunction?

The repair time can vary based on the specific issue causing the code. Simple fixes like cleaning connectors may take less time, while replacing a faulty rain sensor module could require more extensive work.