Quick Answer
C0708 means: C0708 indicates a communication failure between the Transmission Control Module and the Engine Control Module.
Can I drive with C0708? Immediate attention is recommended to avoid further transmission damage.
Common Questions
What does C0708 mean and how does it affect my car?
C0708 indicates a communication error between the Transmission Control Module and the Engine Control Module. This affects shifting, acceleration, and may lead to severe transmission issues if not addressed promptly.
What are the most common causes of C0708 and how much does it cost to fix?
Common causes include a faulty TCM (around 40% likelihood) and corroded wiring (30%). Repair costs can range from $150 for wiring repairs to $1200 for TCM replacement.
Can I drive my car with C0708 or should I stop immediately?
It's advisable to stop driving your car immediately if you see the C0708 code. Continuing to drive can lead to transmission failure, which is costly to fix.
How can I diagnose C0708 myself using GeekOBD APP?
Start by using the GeekOBD APP to scan for codes and retrieve freeze frame data. Look for wiring issues or connector problems that may be indicated in the data.
What vehicles are most commonly affected by C0708?
Vehicles like the 2014-2018 Ford Fusion and 2015-2019 Chevrolet Malibu frequently experience the C0708 code due to wiring or TCM issues.
How can I prevent C0708 from happening again?
Regular maintenance checks on wiring and connectors, along with software updates for your TCM, can help prevent the occurrence of the C0708 code.
What is C0708?
The C0708 diagnostic trouble code refers to a communication error between the Transmission Control Module (TCM) and the vehicle’s Engine Control Module (ECM). This code can indicate several underlying issues that may affect the vehicle's performance and drivability. When the TCM fails to communicate effectively with the ECM, it can lead to erratic shifting, poor acceleration, and even engine stalling. This situation is particularly common in vehicles like the 2014-2018 Ford Fusion and the 2015-2019 Chevrolet Malibu, where electrical problems often cause such communication errors. In many cases, this code can be triggered by faulty wiring, corroded connectors, or a malfunctioning TCM itself. Ignoring this code can lead to more serious transmission issues, including complete transmission failure, which can be costly to repair. Therefore, understanding the implications of a C0708 code is crucial for vehicle owners to maintain their car's performance and ensure safe driving conditions.
System: C - Chassis (ABS, Steering, Suspension)
Symptoms
Common symptoms when C0708 is present:
- Check engine light illuminates and stays on, indicating a persistent issue that requires attention.
- Erratic shifting behavior, where the vehicle hesitates or shifts harshly during acceleration.
- Decreased fuel economy, often resulting in a noticeable drop of 10-15% in efficiency due to improper transmission operation.
- Engine stalling during operation, which can pose safety risks while driving.
- Transmission slipping or failure to engage properly, leading to reduced vehicle performance.
Possible Causes
Most common causes of C0708 (ordered by frequency):
- Faulty Transmission Control Module (TCM) - Likelihood: 40%. A common issue where the TCM itself malfunctions, requiring replacement.
- Corroded or damaged wiring - Likelihood: 30%. Worn or frayed wires can disrupt communication between the TCM and ECM.
- Poor connection at TCM or ECM connectors - Likelihood: 20%. Loose or corroded connections can lead to intermittent communication failures.
- Software glitches in the TCM - Likelihood: 5%. Occasionally, software updates or resets may be needed to restore normal function.
- Rarely, physical damage to the TCM from an accident or water ingress - Likelihood: 5%. This requires extensive repairs or replacement.
C0708 Repair Costs
Cost Breakdown by Repair Type
TCM Replacement
Replacing the faulty Transmission Control Module with a new or refurbished unit.
- Total: $600 - $1200
- Success rate: 85%
Wiring Repair
Repairing or replacing damaged wiring that affects communication.
- Total: $150 - $300
- Success rate: 75%
Money-Saving Tips for C0708
- 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 C0708 Diagnosis Process
Follow these systematic steps to accurately diagnose C0708. 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).
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).
Step 3: Step 3: Component testing - Use a multimeter to test voltage and continuity at TCM and ECM connectors (20-30 minutes)
Step 3: Component testing - Use a multimeter to test voltage and continuity at TCM and ECM connectors (20-30 minutes).
Step 4: Step 4: System function test - Verify proper operation of the transmission after repairs and clear codes (10-15 minutes)
Step 4: System function test - Verify proper operation of the transmission after repairs and clear codes (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success (15-20 minutes).
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: 2016 Ford Fusion with C0708 Code
Vehicle: 2016 Ford Fusion, 75000 miles
Problem: Customer reported erratic shifting and check engine light.
Diagnosis: Performed an OBD2 scan with GeekOBD APP, confirmed C0708 code. Inspected wiring and found damaged connectors.
Solution: Replaced damaged connectors and performed a TCM reset.
Cost: $350 (including parts and labor)
Result: Customer reported smooth shifting and no further issues.
Case Study 2: 2017 Chevrolet Malibu C0708 Diagnosis
Vehicle: 2017 Chevrolet Malibu, 60000 miles
Problem: Vehicle had poor acceleration and check engine light illuminated.
Diagnosis: Used GeekOBD APP for diagnosis, confirmed C0708 code. Conducted wiring inspection and found corrosion.
Solution: Repaired corroded wiring and replaced the TCM.
Cost: $900 (detailed breakdown for parts and labor)
Result: Vehicle performance improved significantly post-repair.