AutoCodes – Generic – B393B

B393B Code - Air Conditioning Compressor Valve Control Circuit

Quick Answer

This A/C system uses a conventional clutch to engage and mechanically turn the compressor and a variable displacement solenoid valve to alter the amount of displacement created by the turning of the compressor. Common causes include Faulty Air Conditioning Compressor, Air Conditioning Compressor harness is open or shorted, Air Conditioning Compressor 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: B393B indicates Air Conditioning Compressor Valve Control Circuit.
Common causes: Common causes include Faulty Air Conditioning Compressor, Air Conditioning Compressor harness is open or shorted, Air Conditioning Compressor 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 18,093

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 Jun 17, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B393B Description

This A/C system uses a conventional clutch to engage and mechanically turn the compressor and a variable displacement solenoid valve to alter the amount of displacement created by the turning of the compressor. The Heating, Ventilation, and Air Conditioning (HVAC) Control Module provides both switched battery voltage and a pulse width modulated ground to the variable displacement solenoid valve. When the A/C switch is pressed, the HVAC Control Module grounds the variable displacement solenoid using a Pulse Width Modulation (PWM) signal in order to determine the amount of compressor displacement. The performance of the A/C compressor is based on adjusted interior temperature and engine load. The Diagnostic Trouble Code (DTC) sets when a PWM greater than 10% is sent but no current is read back.

OBDII Code B393B - Air Conditioning Compressor Valve Control Circuit - AutoCodes.com — B393B Code - Air Conditioning Compressor Valve Control Circuit

What does this mean?

What are the Possible Causes of the DTC B393B?

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

How to Fix the DTC B393B?

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 B393B 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 B393B code?

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Need Help with the Code?

Get the B393B code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B393B Buick — Air Conditioning Compressor Valve Control Circuit
B393B Cadillac — Air Conditioning Compressor Valve Control Circuit
B393B Chevrolet — Air Conditioning Compressor Valve Control Circuit
B393B GMC — Air Conditioning Compressor Valve Control Circuit
B393B Pontiac — Air Conditioning Compressor Valve Control Circuit
B393B Saturn — Air Conditioning Compressor Valve Control Circuit

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 B393B Code

1. What are the common symptoms of OBDII code B393B related to the Air Conditioning Compressor Valve Control Circuit?

- Common symptoms include a malfunctioning air conditioning system, lack of cooling, and possible illumination of the check engine light.

2. What are some possible causes of OBDII code B393B?

- Possible causes include a faulty air conditioning compressor valve, damaged wiring or connectors in the circuit, or a defective control module.

3. How can I diagnose the issue related to the Air Conditioning Compressor Valve Control Circuit?

- Diagnosis typically involves using an OBDII scanner to read the code, inspecting the wiring and connectors for damage, and testing the compressor valve and control module.

4. Can I drive my vehicle with OBDII code B393B present?

- While it may be possible to drive with this code, it is recommended to have the issue addressed promptly to prevent further damage to the air conditioning system.

5. How can I repair OBDII code B393B related to the Air Conditioning Compressor Valve Control Circuit?

- Repair steps may include replacing the faulty compressor valve, repairing damaged wiring or connectors, or reprogramming the control module as necessary.

6. Is it safe to attempt DIY repairs for OBDII code B393B?

- DIY repairs are possible for those with automotive repair experience and the necessary tools. However, seeking professional help is recommended for accurate diagnosis and proper repair.

7. What is the typical cost to repair OBDII code B393B?

- The cost of repair can vary depending on the specific issue, parts needed, and labor rates. It is advisable to obtain quotes from local automotive repair shops.

8. Can OBDII code B393B be triggered by other issues unrelated to the Air Conditioning Compressor Valve Control Circuit?

- While rare, it is possible for this code to be triggered by other electrical or control module issues within the vehicle's system. Proper diagnosis is essential.

9. Will resetting the check engine light clear OBDII code B393B?

- Resetting the check engine light may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear.

10. How important is it to fix OBDII code B393B promptly?

- It is important to address this code promptly to ensure the proper functioning of the air conditioning system and prevent potential damage to other components.