U079F - Communication Error Between Control Modules in Various Vehicles

Quick Answer

U079F means: U079F indicates a communication error between the Body Control Module and Engine Control Module.

Fix: Check and replace faulty components Cost: $100 - $300 Time: 90-180 minutes

Can I drive with U079F? Immediate attention is recommended to prevent further electrical issues.

Common Questions

What does U079F mean and how does it affect my car?

The U079F code signifies a communication breakdown between the Body Control Module and Engine Control Module, which can lead to various performance issues in your vehicle. When these modules can't talk to each other, it may cause problems like erratic dashboard readings, malfunctioning lights, or even engine performance issues. If you notice any of these symptoms, it's essential to address this code swiftly to prevent further complications.

What are the most common causes of U079F and how much does it cost to fix?

Common causes of the U079F code include faulty wiring (40%), malfunctioning BCM (30%), and issues within the ECM (20%). Repair costs can range from $100 for wiring repairs to $600 for replacing the BCM. On average, expect to spend between $150 to $400 for ECM reprogramming. Always consult with a professional technician to get an accurate diagnosis and cost estimate.

Can I drive my car with U079F or should I stop immediately?

Driving with a U079F code is not advisable, as it can lead to safety issues. The communication failure may cause critical systems to malfunction, impacting vehicle performance and safety features. If you see this code, it's best to consult a technician and address the issue before continuing to drive.

How can I diagnose U079F myself using GeekOBD APP?

To diagnose the U079F code using the GeekOBD APP, start by connecting the app to your vehicle's OBD-II port. Use the app to scan for all diagnostic trouble codes and access freeze frame data for context. Look for any related codes that could indicate the source of the problem. Follow the provided diagnostic steps for a thorough assessment of the BCM and ECM.

What vehicles are most commonly affected by U079F?

The U079F code is frequently seen in various models from GM brands, particularly in 2015-2018 Chevrolet Silverado, GMC Sierra, and Cadillac Escalade. Be sure to check for any known recalls or technical service bulletins (TSBs) related to this code for your specific vehicle.

How can I prevent U079F from happening again?

To prevent the U079F code from recurring, ensure regular maintenance of your vehicle's electrical systems. Inspect wiring and connectors for signs of wear and corrosion, especially if you live in areas with harsh weather. Additionally, avoid aftermarket modifications that could interfere with the vehicle's electronics. Keeping your software updated can also help maintain communication between modules.

What is U079F?

The U079F diagnostic trouble code (DTC) indicates a communication error between control modules within your vehicle. Specifically, this code is associated with the Body Control Module (BCM) and the Engine Control Module (ECM). When these modules fail to communicate effectively, you may experience a range of issues affecting your vehicle's performance, safety, and comfort features. Commonly seen in makes like Chevrolet, GMC, and Cadillac, this issue can lead to problems such as malfunctioning lights, erratic speedometer readings, or even difficulty starting the engine. The root of the problem could be due to faulty wiring, a malfunctioning BCM, or issues within the ECM itself. Owners should take this code seriously, as it may indicate underlying electrical problems that could escalate if left unaddressed. Ignoring the U079F code may lead to further complications, including more extensive repairs down the line. If you suspect this error code in your vehicle, it’s crucial to consult a professional automotive technician who can diagnose and resolve the issue effectively.

System: U - Network (Communication, CAN Bus)

Symptoms

Common symptoms when U079F is present:

  • Check engine light stays on constantly, indicating the vehicle's onboard diagnostic system has detected an issue that needs addressing.
  • Malfunctioning dashboard lights or gauges, which may flicker or give inaccurate readings, leading to confusion while driving.
  • Engine hesitates during acceleration, which can be a safety issue if the vehicle fails to respond as expected.
  • Erratic behavior of power windows or door locks, which might stop working intermittently or respond sluggishly.
  • Fuel economy decreased by 10-15%, potentially due to the ECM not optimizing fuel usage effectively.

Possible Causes

Most common causes of U079F (ordered by frequency):

  1. Faulty wiring connections between the BCM and ECM, with a likelihood of around 40% due to wear and tear or corrosion.
  2. A malfunctioning Body Control Module (BCM) is another common cause, seen in about 30% of cases, often due to software glitches or physical damage.
  3. Issues within the Engine Control Module (ECM) itself account for around 20%, caused by software issues or component failure.
  4. Less common but serious causes include short circuits or damaged harnesses, which can lead to more significant electrical problems.
  5. Rarely, external factors like aftermarket accessories or modifications can interfere with module communication, though this is less frequent.

U079F Repair Costs

Cost Breakdown by Repair Type

Wiring Repair

Repairing damaged wiring or connectors between the BCM and ECM.

  • Total: $100 - $300
  • Success rate: 85%
BCM Replacement

Replacing the faulty Body Control Module.

  • Total: $300 - $600
  • Success rate: 90%
ECM Reprogramming

Reprogramming the ECM to resolve software issues.

  • Total: $150 - $400
  • Success rate: 80%
Money-Saving Tips for U079F
  • 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 U079F Diagnosis Process

Follow these systematic steps to accurately diagnose U079F. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)

Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (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 - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)

Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (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 - Use a multimeter or specific diagnostic tools to test the BCM and ECM for faults (20-30 minutes)

Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the BCM and ECM for faults (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 - Verify proper operation after repairs and clear codes using the GeekOBD APP (10-15 minutes)

Step 4: System function test - Verify proper operation after repairs and clear codes using the GeekOBD APP (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 - Drive the vehicle under various conditions to confirm the repair success (15-20 minutes)

Step 5: Road test verification - Drive the vehicle under various conditions to confirm the repair success (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: 2017 Chevrolet Silverado - U079F Diagnosis and Repair

Vehicle: 2017 Chevrolet Silverado LT, 60,000 miles

Problem: Customer reported that the check engine light was on and experienced erratic dashboard readings.

Diagnosis: After scanning with the GeekOBD APP, the U079F code was confirmed. A visual inspection revealed corroded wiring connections to the BCM.

Solution: Repaired the wiring connections, cleaned the terminals, and re-scanned to confirm the code was cleared.

Cost: $250 (including labor and materials)

Result: The check engine light was cleared, and subsequent tests showed normal operation of dashboard components.

Case Study 2: 2016 Cadillac Escalade - BCM Replacement

Vehicle: 2016 Cadillac Escalade, 75,000 miles

Problem: Customer complained of intermittent electrical issues and dashboard lights flickering.

Diagnosis: Scan results confirmed U079F. Further diagnostics indicated a malfunctioning BCM that was not responding correctly.

Solution: Replaced the BCM and performed a software update to ensure proper functionality.

Cost: $550 (parts and labor included)

Result: Post-repair, all electrical systems operated normally, and the U079F code did not return.

Diagnose U079F

Use GeekOBD APP for professional diagnosis!

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Code Information

Code: U079F
System: Network (Communication, CAN Bus)
Severity: HIGH
Category: Network Codes