U0708 - Transmission Control Module Communication Issue in Chrysler, Ford, and GM Vehicles

Quick Answer

U0708 means: DTC U0708 signifies a communication issue between the Transmission Control Module and other vehicle control units.

Fix: Check and replace faulty components Cost: $400 - $800 Time: 90-180 minutes

Can I drive with U0708? Immediate attention is advised to avoid transmission damage.

Common Questions

What does U0708 mean and how does it affect my car?

DTC U0708 indicates a communication issue between the Transmission Control Module and other vehicle systems. This can lead to poor transmission performance, such as erratic shifting or complete failure to engage gears. If left unresolved, it can result in serious mechanical damage and costly repairs.

What are the most common causes of U0708 and how much does it cost to fix?

Common causes of U0708 include a faulty TCM, wiring issues, or a malfunctioning engine control unit. Repair costs can vary widely, with TCM replacement ranging from $400 to $800, while wiring repairs might be between $100 to $300.

Can I drive my car with U0708 or should I stop immediately?

It's advisable to stop driving the vehicle if you see the U0708 code due to potential transmission failure, which can lead to unsafe driving conditions. Addressing the issue promptly can help prevent further damage.

How can I diagnose U0708 myself using GeekOBD APP?

To diagnose U0708 using the GeekOBD APP, first, connect the app to your vehicle’s OBD2 port. Run a complete scan to identify all DTCs and check the freeze frame data for context. Pay attention to the live data to spot any irregularities in the TCM's operation.

What vehicles are most commonly affected by U0708?

DTC U0708 is frequently seen in 2010-2020 models of Chrysler, Ford, and GM vehicles, particularly those with advanced transmission systems. Notable examples include the 2015-2018 Ford F-150 and 2013-2017 Chevy Silverado.

How can I prevent U0708 from happening again?

To prevent U0708 from recurring, ensure regular maintenance of your vehicle's electrical systems, check wiring and connections periodically, and address any transmission-related issues promptly. Using quality parts during repairs can also help prevent future problems.

What is U0708?

The Diagnostic Trouble Code (DTC) U0708 indicates a communication malfunction between the Transmission Control Module (TCM) and other control modules in the vehicle. This can occur in various makes and models, particularly in Chrysler, Ford, and General Motors vehicles manufactured between 2010 and 2020. When this code is triggered, it usually points to an issue with the TCM that can prevent the transmission from functioning properly. Drivers may experience erratic shifting, failure to engage gears, or even a complete loss of transmission functionality. The TCM is responsible for sending and receiving information from the engine control unit (ECU) and other modules, such as the body control module (BCM). A communication error can cause the TCM to misinterpret engine data, leading to poor performance and potential safety hazards. It's critical for car owners to address this issue promptly, as ignoring the code may lead to more severe transmission damage or a complete failure, resulting in costly repairs. If you're facing issues with your vehicle's transmission, understanding DTC U0708 is the first step in diagnosing and resolving the problem effectively.

System: U - Network (Communication, CAN Bus)

Symptoms

Common symptoms when U0708 is present:

  • Check engine light remains illuminated, indicating an ongoing issue that needs immediate attention.
  • Erratic shifting behavior, where the vehicle may shift gears unexpectedly or harshly, leading to a jerky driving experience.
  • Transmission may fail to engage or slip, especially when accelerating, causing a frustrating and potentially dangerous situation.
  • Increased fuel consumption, as the engine may work harder to compensate for incorrect shifting patterns.
  • Unusual noises from the transmission, such as grinding or whining, which can indicate deeper mechanical issues.

Possible Causes

Most common causes of U0708 (ordered by frequency):

  1. The most common cause is a faulty Transmission Control Module, with a likelihood of around 50%. This can arise from internal component failure or software corruption.
  2. Wiring issues or poor connections between the TCM and other modules account for about 30% of cases. Corroded connectors or damaged wiring harnesses can interrupt communication.
  3. A second potential cause is a malfunctioning engine control unit, which can misinterpret data from the TCM and lead to incorrect operation.
  4. Less common, but serious, is the issue of internal transmission problems that may prevent the TCM from receiving proper feedback.
  5. A rare cause could be a failed body control module, which can disrupt communication with the TCM, although this is less frequently seen.

U0708 Repair Costs

Cost Breakdown by Repair Type

TCM Replacement

Replacing the faulty Transmission Control Module with a new or refurbished unit.

  • Total: $400 - $800
  • Success rate: 85%
Wiring Repair

Repairing damaged wiring and connections to restore proper communication.

  • Total: $100 - $300
  • Success rate: 70%
Money-Saving Tips for U0708
  • 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 U0708 Diagnosis Process

Follow these systematic steps to accurately diagnose U0708. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Conduct an initial visual inspection to check for damaged wiring, loose connections, or corrosion around the TCM and related components (5-10 minutes)

Step 1: Conduct an initial visual inspection to check for damaged wiring, loose connections, or corrosion around the TCM and related components (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: Use the GeekOBD APP to perform a comprehensive OBD2 scan to retrieve all codes and freeze frame data, which helps in understanding the context of the fault (10-15 minutes)

Step 2: Use the GeekOBD APP to perform a comprehensive OBD2 scan to retrieve all codes and freeze frame data, which helps in understanding 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: Carry out component testing using a multimeter to check voltage and ground signals at the TCM and associated wiring (20-30 minutes)

Step 3: Carry out component testing using a multimeter to check voltage and ground signals at the TCM and associated wiring (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: Perform a system function test after making any necessary repairs to ensure the TCM operates correctly and clear the codes (10-15 minutes)

Step 4: Perform a system function test after making any necessary repairs to ensure the TCM operates correctly and clear the codes (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: Conduct a road test under various driving conditions to verify the success of the repair and ensure the absence of any DTCs (15-20 minutes)

Step 5: Conduct a road test under various driving conditions to verify the success of the repair and ensure the absence of any DTCs (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 in a 2015 Chrysler 300

Vehicle: 2015 Chrysler 300, 60,000 miles

Problem: Customer reported transmission slipping and the check engine light illuminated.

Diagnosis: Initial scans revealed DTC U0708 along with other transmission-related codes. A visual inspection showed corrosion on the TCM connector.

Solution: Replaced the TCM and cleaned the connectors. After reprogramming the new module, test drives showed normal operation.

Cost: $750 (including parts and labor)

Result: The transmission operated smoothly post-repair with no further codes.

Case Study 2: Wiring Repair on a 2016 Ford Explorer

Vehicle: 2016 Ford Explorer, 75,000 miles

Problem: Owner experienced erratic shifting and the check engine light was on.

Diagnosis: DTC U0708 was diagnosed along with a wiring issue found during inspection of the harness.

Solution: Repaired the damaged wiring and re-established proper connections. The TCM was tested and confirmed to be functioning well.

Cost: $250 (for wiring repair and labor)

Result: Post-repair, the vehicle showed no further issues and the owner reported improved transmission performance.

Diagnose U0708

Use GeekOBD APP for professional diagnosis!

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Code Information

Code: U0708
System: Network (Communication, CAN Bus)
Severity: HIGH
Category: Network Codes