B0679 - Understanding the Air Conditioning Control Module Error in 2010-2019 Chevrolet and GMC Models

Quick Answer

B0679 means: B0679 indicates an air conditioning control module malfunction.

Fix: Check and replace faulty components Cost: $300 - $600 Time: 90-180 minutes

Can I drive with B0679? Seek diagnosis soon to prevent further HVAC system damage.

Common Questions

What does B0679 mean and how does it affect my car?

The B0679 code indicates a problem with your air conditioning control module, which can lead to issues with temperature control and overall HVAC performance. Addressing this promptly can improve comfort and prevent further system damage.

What are the most common causes of B0679 and how much does it cost to fix?

Common causes include a faulty control module, damaged wiring, or refrigerant issues. Repair costs can range from $100 for wiring repairs to $600 for complete module replacement.

Can I drive my car with B0679 or should I stop immediately?

While you can drive, it’s advisable to address the B0679 code soon to ensure your AC system functions properly, especially in extreme temperatures.

How can I diagnose B0679 myself using GeekOBD APP?

Using the GeekOBD APP, you can scan for codes and view freeze frame data. This helps you understand when the issue occurs and can guide you in pinpointing the problem.

What vehicles are most commonly affected by B0679?

The B0679 code is frequently seen in 2010-2019 Chevrolet and GMC models, particularly those with advanced climate control systems.

How can I prevent B0679 from happening again?

Regular maintenance, including checking the AC system for leaks and ensuring proper refrigerant levels, can help prevent the recurrence of B0679.

What is B0679?

The diagnostic trouble code (DTC) B0679 indicates a malfunction within the air conditioning control module (ACCM) in your vehicle. Specifically, this code signifies that the ACCM has detected a fault in its internal circuitry or communication with other modules. This issue can lead to problems with your vehicle's air conditioning system, resulting in inadequate cooling or heating performance. In many 2010-2019 Chevrolet and GMC models, this can manifest as an unresponsive climate control system, where settings for temperature and fan speed may not adjust as intended. If left unaddressed, it can lead to further complications, including potential damage to the HVAC system's components and increased repair costs down the line. Drivers may notice symptoms like unusual noises from the AC system, fluctuating temperatures, or even complete failure of the air conditioning, particularly on hot summer days. Understanding this code and addressing it promptly can help maintain vehicle comfort and performance, ensuring that your car remains a reliable mode of transportation.

System: B - Body (Airbags, Lighting, Security, Climate Control)

Symptoms

Common symptoms when B0679 is present:

  • The check engine light illuminates, often accompanied by the AC not functioning properly.
  • Inconsistent temperature output from the air conditioning system, making it difficult to maintain comfort.
  • Fan speed does not respond to adjustments, leading to either no airflow or constant maximum speed.
  • Unusual noises, such as clicking or grinding, may be heard when the AC is activated, indicating potential internal component issues.
  • The AC system may cycle on and off unexpectedly, reducing overall efficiency and causing discomfort.

Possible Causes

Most common causes of B0679 (ordered by frequency):

  1. The most common cause of B0679 is a faulty air conditioning control module, which has a likelihood of about 60%. This can arise from electrical shorts or component failures.
  2. Another possible cause is damaged wiring or connectors in the ACCM circuit, which can lead to intermittent failures and is seen in approximately 25% of cases.
  3. Poor refrigerant levels or leaks can also trigger the code, as the ACCM may not receive the signals needed for proper operation. Regular inspections can help prevent this issue.
  4. Less commonly, software issues in the vehicle’s onboard diagnostic system can create false readings, accounting for about 10% of B0679 occurrences.
  5. A rare but serious cause could be a complete failure of the HVAC control unit, which may require extensive diagnostics and replacement.

B0679 Repair Costs

Cost Breakdown by Repair Type

AC Control Module Replacement

Replacing the faulty air conditioning control module.

  • Total: $300 - $600
  • Success rate: 85%
Wiring Repair

Repairing damaged wiring or connectors that may be causing the code.

  • Total: $100 - $300
  • Success rate: 75%
Software Update

Updating the vehicle’s software to resolve potential software-related issues.

  • Total: $50 - $150
  • Success rate: 70%
Money-Saving Tips for B0679
  • Start with the most common and least expensive repairs first
  • Use GeekOBD APP to confirm diagnosis before replacing expensive parts
  • Consider preventive maintenance to avoid future occurrences
  • Compare prices for OEM vs aftermarket parts based on your needs
  • Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional B0679 Diagnosis Process

Follow these systematic steps to accurately diagnose B0679. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Initial visual inspection - Begin by checking for any visible wiring damage, loose connections, or corrosion around the ACCM and its connectors (5-10 minutes)

Step 1: Initial visual inspection - Begin by checking for any visible wiring damage, loose connections, or corrosion around the ACCM and its connectors (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: OBD2 scan with GeekOBD APP - Use the GeekOBD APP to retrieve all diagnostic codes and freeze frame data to understand the context of the fault (10-15 minutes)

Step 2: OBD2 scan with GeekOBD APP - Use the GeekOBD APP to retrieve all diagnostic codes and freeze frame data to understand the context of the fault (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Component testing - Employ a multimeter to test the ACCM and associated circuitry for proper voltage and continuity (20-30 minutes)

Step 3: Component testing - Employ a multimeter to test the ACCM and associated circuitry for proper voltage and continuity (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: System function test - After repairs, verify the operation of the air conditioning system and clear any stored codes to ensure they do not return (10-15 minutes)

Step 4: System function test - After repairs, verify the operation of the air conditioning system and clear any stored codes to ensure they do not return (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Road test verification - Take the vehicle for a test drive under various conditions to confirm that the air conditioning system functions correctly (15-20 minutes)

Step 5: Road test verification - Take the vehicle for a test drive under various conditions to confirm that the air conditioning system functions correctly (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

Important Notes

  • Always verify the repair with GeekOBD APP after completing diagnostic steps
  • Clear codes and test drive to ensure the problem is resolved
  • Address underlying causes to prevent code recurrence

Real Repair Case Studies

Case Study 1: AC Control Module Replacement on a 2016 Chevrolet Silverado

Vehicle: 2016 Chevrolet Silverado, 75,000 miles

Problem: Customer reported that the air conditioning system would not cool and the climate control settings were unresponsive.

Diagnosis: After scanning for DTCs with GeekOBD, B0679 was retrieved. Visual inspection showed no wiring damage, but the ACCM failed component tests.

Solution: Replaced the air conditioning control module and cleared the codes. The system function was verified post-repair.

Cost: $450 (including parts and labor)

Result: AC system returned to optimal performance with no further issues noted.

Case Study 2: Wiring Repair on a 2014 GMC Sierra

Vehicle: 2014 GMC Sierra, 90,000 miles

Problem: Driver experienced fluctuating air conditioning temperatures and occasional system failure.

Diagnosis: OBD scan revealed B0679. Inspection showed corroded connectors leading to intermittent signal loss.

Solution: Repaired the damaged wiring and connectors, ensuring good electrical continuity.

Cost: $150 (including parts and labor)

Result: The air conditioning system functioned reliably after the repair.

Diagnose B0679

Use GeekOBD APP for professional diagnosis!

  • Real-time data monitoring
  • Advanced diagnostic features
  • Step-by-step repair guidance
  • Professional-grade analysis
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Code Information

Code: B0679
System: Body (Airbags, Lighting, Security, Climate Control)
Severity: MEDIUM
Category: Body Codes