U0656 - Understanding DTC U0656: Communication Issue in 2010-2020 Ford and Chevy Models

Quick Answer

U0656 means: U0656 indicates a communication problem between vehicle control modules.

Fix: Check and replace faulty components Cost: $150 - $300 Time: 90-180 minutes

Can I drive with U0656? Immediate diagnosis and repair recommended to avoid further damage.

Common Questions

What does U0656 mean and how does it affect my car?

The U0656 code signals a communication problem between your vehicle's modules, affecting essential operations like transmission shifting. This can lead to performance issues, and it's crucial to diagnose it as soon as possible to avoid further damage.

What are the most common causes of U0656 and how much does it cost to fix?

Common causes include wiring issues and faulty transmission modules. Repair costs can range from $150 for wiring repair to $1000 for module replacement, depending on the severity of the issue.

Can I drive my car with U0656 or should I stop immediately?

It's advised to avoid driving the vehicle until the issue is resolved, as ignoring the U0656 code can lead to significant transmission damage and safety concerns.

How can I diagnose U0656 myself using GeekOBD APP?

Using the GeekOBD APP, you can scan for diagnostic codes, review freeze frame data, and even monitor live data to identify potential issues with your vehicle's transmission and engine control modules.

What vehicles are most commonly affected by U0656?

Many Ford and Chevrolet models manufactured between 2010 and 2020, including the Ford F-150 and Chevy Silverado, frequently experience this code due to their reliance on complex electronic control systems.

How can I prevent U0656 from happening again?

Regular vehicle maintenance, including inspecting wiring and connectors, ensuring software updates are applied, and addressing any electrical issues promptly can help prevent the recurrence of U0656.

What is U0656?

DTC U0656 is a diagnostic trouble code indicating an issue with communication between the vehicle's modules, particularly related to the transmission control module (TCM) and the engine control module (ECM). This trouble code can arise from various factors, including wiring problems, module failures, or software issues. When U0656 is triggered, it means that the TCM is unable to communicate correctly with other control modules, which can lead to erratic vehicle behavior, including shift problems or even a no-start condition. For instance, if you own a 2015 Ford F-150, you may notice that the transmission is not shifting smoothly or that the check engine light is illuminated. Ignoring this code can result in more severe transmission issues over time, leading to costly repairs. It’s crucial to address U0656 promptly to maintain your vehicle's performance and reliability.

System: U - Network (Communication, CAN Bus)

Symptoms

Common symptoms when U0656 is present:

  • The check engine light remains on continuously, indicating a persistent issue that needs attention.
  • You may experience transmission hesitation during acceleration, which can feel like the vehicle is struggling to shift gears.
  • Fuel economy might drop significantly, with reports of reductions between 10-15%, impacting your overall driving costs.
  • The vehicle may enter limp mode, limiting engine power and causing the car to drive sluggishly.
  • Unresponsive gear shifts can occur, making it difficult to change gears smoothly while driving.

Possible Causes

Most common causes of U0656 (ordered by frequency):

  1. Wiring issues are the most common cause of U0656, accounting for about 60% of cases. This can include damaged or corroded wires that disrupt communication between modules.
  2. A faulty transmission control module (TCM) is another significant cause, often resulting from software glitches or internal component failures.
  3. Poor electrical connections, especially at the TCM or ECM, account for around 15% of U0656 codes. Regular inspections can help prevent this.
  4. Less common causes include a failing engine control module (ECM), which can lead to more severe performance issues.
  5. Rarely, a software update from the manufacturer may be required to resolve communication problems between modules.

U0656 Repair Costs

Cost Breakdown by Repair Type

Wiring Repair

Repairing or replacing damaged wiring harnesses that connect the TCM and ECM.

  • Total: $150 - $300
  • Success rate: 85%
Transmission Control Module Replacement

Replacing a faulty TCM with a new or refurbished unit.

  • Total: $500 - $1000
  • Success rate: 90%
Software Update

Updating the TCM or ECM software to resolve communication issues.

  • Total: $100 - $200
  • Success rate: 75%
Money-Saving Tips for U0656
  • 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 U0656 Diagnosis Process

Follow these systematic steps to accurately diagnose U0656. 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 to test the voltage and ground at the TCM and ECM connectors (20-30 minutes)

Step 3: Component testing - Use a multimeter to test the voltage and ground at the TCM and ECM connectors (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 GeekOBD APP (10-15 minutes)

Step 4: System function test - Verify proper operation after repairs and clear codes using 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 repair success and monitor for any reoccurring issues (15-20 minutes)

Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success and monitor for any reoccurring issues (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: Transmission Control Module Replacement on 2016 Ford F-150

Vehicle: 2016 Ford F-150, 85,000 miles

Problem: Customer reported erratic shifting and check engine light on.

Diagnosis: After scanning with the GeekOBD APP, U0656 was confirmed, and a visual inspection revealed corroded wiring.

Solution: Wiring was repaired, and the TCM was replaced due to internal failure.

Cost: $850 (including parts and labor)

Result: The vehicle shifted smoothly post-repair, and the check engine light remained off.

Case Study 2: Wiring Repair on 2018 Chevy Silverado

Vehicle: 2018 Chevy Silverado, 60,000 miles

Problem: Customer experienced transmission hesitation and check engine light.

Diagnosis: GeekOBD APP showed U0656; inspection found damaged wiring at the TCM connector.

Solution: Repaired the wiring harness and secured connections.

Cost: $200 (including parts and labor)

Result: The issue was resolved, and the vehicle performed normally afterward.

Diagnose U0656

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: U0656
System: Network (Communication, CAN Bus)
Severity: HIGH
Category: Network Codes