U0923 - Communication Bus A Off (Common in 2015-2020 Ford F-150, 2016-2021 Chevrolet Silverado)

Quick Answer

U0923 means: U0923 indicates a missing communication message between vehicle control modules.

Fix: Check and replace faulty components Cost: $300 - $1200 Time: 90-180 minutes

Can I drive with U0923? Immediate attention recommended to prevent further electrical issues.

Common Questions

What does U0923 mean and how does it affect my car?

U0923 signifies a communication failure in your vehicle’s control modules. This can lead to various issues, such as erratic dashboard readings, malfunctioning lights, or even impaired driving performance, making it crucial to address promptly.

What are the most common causes of U0923 and how much does it cost to fix?

Common causes include faulty control modules (40% of cases), wiring issues (30%), and CAN bus malfunctions. Repair costs can range from $100 for minor wiring repairs to over $1200 for module replacements.

Can I drive my car with U0923 or should I stop immediately?

While it may be possible to drive with the U0923 code, doing so can lead to further issues. It’s advised to address the problem as soon as possible to avoid safety risks or additional damage.

How can I diagnose U0923 myself using GeekOBD APP?

Using the GeekOBD APP, start by scanning for all diagnostic trouble codes. Review any freeze-frame data for context. Check the status of control modules and look for communication errors or failed modules.

What vehicles are most commonly affected by U0923?

U0923 is frequently observed in 2015-2020 Ford F-150s and 2016-2021 Chevrolet Silverados. Issues can arise due to recalls or known technical service bulletins (TSBs) for these models.

How can I prevent U0923 from happening again?

Regularly inspect wiring and connections for wear and corrosion. Keep your vehicle’s software updated and ensure that diagnostic checks are part of routine maintenance to catch potential issues early.

What is U0923?

DTC U0923 indicates a communication error within the vehicle's controller area network (CAN) bus system, specifically noting that a message that should have been received from a control module is missing. This code typically arises when one of the control modules, such as the transmission control module or body control module, fails to communicate effectively with other modules in the vehicle. When this happens, it can lead to various operational issues, including problems with lighting, stability control, or even engine performance in some cases. It’s important to recognize that while this code might not trigger a 'Check Engine' light immediately, it can lead to symptoms that affect vehicle safety and performance. For instance, you might notice erratic electrical behavior, such as warning lights flickering or malfunctioning gauges. Additionally, if multiple modules are affected, it could indicate a more significant issue within the vehicle's electrical system, which may require extensive diagnostic testing and repairs. Addressing the U0923 code promptly is crucial to prevent further complications and ensure the vehicle operates safely and reliably.

System: U - Network (Communication, CAN Bus)

Symptoms

Common symptoms when U0923 is present:

  • The 'Check Engine' light may illuminate or remain on, indicating a communication fault.
  • Gauges on the dashboard may behave erratically, with speed or fuel readings fluctuating unexpectedly.
  • Electrical components such as lights or windows may operate inconsistently, suggesting potential wiring issues.
  • You might experience delayed or unresponsive actions from the vehicle's systems, such as failing to shift properly or delayed starting.
  • In more severe cases, the vehicle may enter limp mode, reducing power and limiting functionality to prevent further damage.

Possible Causes

Most common causes of U0923 (ordered by frequency):

  1. The most common cause is a faulty control module, which could account for around 40% of U0923 cases. When a module fails, it may stop sending or receiving messages.
  2. Wiring issues, including damaged connectors or corroded pins, contribute to about 30% of occurrences. Poor connections can disrupt the signal between modules.
  3. Another potential cause is a malfunctioning CAN bus system. This can occur due to electrical shorts or open circuits, often leading to intermittent communication problems.
  4. Less common but serious causes include software malfunctions in the control modules, which can be resolved with updates or reprogramming.
  5. A rare cause could be a complete failure of the vehicle's main electrical harness, which would require significant repairs or replacement.

U0923 Repair Costs

Cost Breakdown by Repair Type

Control Module Replacement

Replacing a faulty control module is often necessary if diagnostics point to module failure.

  • Total: $300 - $1200
  • Success rate: 85%
Wiring Repair

Repairing damaged wiring or connections can often resolve communication issues without replacing modules.

  • Total: $100 - $400
  • Success rate: 75%
Money-Saving Tips for U0923
  • 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 U0923 Diagnosis Process

Follow these systematic steps to accurately diagnose U0923. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Initial visual inspection - Check for obvious signs of damage like frayed wires or loose connectors near the affected modules (5-10 minutes)

Step 1: Initial visual inspection - Check for obvious signs of damage like frayed wires or loose connectors near the affected modules (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 app to retrieve all related codes and freeze frame data to understand the context of the fault (10-15 minutes)

Step 2: OBD2 scan with GeekOBD APP - Use the app to retrieve all related 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 - Utilize a multimeter to test the voltage at connectors and ensure the control modules are receiving power (20-30 minutes)

Step 3: Component testing - Utilize a multimeter to test the voltage at connectors and ensure the control modules are receiving power (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 any repairs, verify the operation of the affected systems and clear the codes from the OBD2 system (10-15 minutes)

Step 4: System function test - After any repairs, verify the operation of the affected systems and clear the codes from the OBD2 system (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 ensure that the repairs have resolved the issues and confirm no codes reappear (15-20 minutes)

Step 5: Road test verification - Drive the vehicle under various conditions to ensure that the repairs have resolved the issues and confirm no codes reappear (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: Control Module Replacement on 2017 Ford F-150

Vehicle: 2017 Ford F-150, 45,000 miles

Problem: Customer reported erratic gauge readings and a persistent 'Check Engine' light.

Diagnosis: After running diagnostics with the GeekOBD APP, the U0923 code was detected along with other communication errors.

Solution: Replaced the faulty transmission control module and reprogrammed it to restore proper communication.

Cost: $950 (parts: $600, labor: $350)

Result: Post-repair, the vehicle's systems operated normally, and the customer reported no further issues.

Case Study 2: Wiring Repair on 2018 Chevrolet Silverado

Vehicle: 2018 Chevrolet Silverado, 30,000 miles

Problem: Client experienced intermittent electrical issues and dashboard warning lights.

Diagnosis: Diagnostic tests indicated U0923 due to damaged wiring near the body control module.

Solution: Repaired the damaged wiring harness and cleaned the connectors.

Cost: $250 (parts: $50, labor: $200)

Result: The issues were resolved, and the vehicle performed reliably after the repairs.

Diagnose U0923

Use GeekOBD APP for professional diagnosis!

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  • Step-by-step repair guidance
  • Professional-grade analysis
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Code Information

Code: U0923
System: Network (Communication, CAN Bus)
Severity: HIGH
Category: Network Codes