Quick Answer
U0673 means: U0673 indicates a communication error between the ECM and TCM.
Can I drive with U0673? Immediate attention is recommended to avoid further transmission damage.
Common Questions
What does U0673 mean and how does it affect my car?
U0673 indicates a communication breakdown between your vehicle's ECM and TCM, potentially leading to transmission issues. If not addressed, it can result in poor performance, erratic shifting, and may even cause the vehicle to enter limp mode, severely limiting driving capability.
What are the most common causes of U0673 and how much does it cost to fix?
Common causes include damaged wiring (60% likelihood) and faulty TCMs. Repair costs can range from $150 for wiring repairs to $800 for a TCM replacement, depending on the specific issue diagnosed.
Can I drive my car with U0673 or should I stop immediately?
It's best to avoid driving the vehicle if U0673 is present, as it can lead to further transmission damage. Immediate diagnostics and repairs are recommended to prevent worsening the problem.
How can I diagnose U0673 myself using GeekOBD APP?
Using the GeekOBD APP, scan your vehicle for diagnostic codes and freeze frame data. Look for any communication errors and inspect the wiring and connectors visually. The app can provide insights into the severity of the issue and suggest steps for further diagnostics.
What vehicles are most commonly affected by U0673?
This code is frequently reported in models like the 2010-2018 Chevrolet Silverado, GMC Sierra, and some Cadillac models. Always check for any recalls or technical service bulletins related to your specific vehicle.
How can I prevent U0673 from happening again?
Regular maintenance checks, especially on wiring and electrical connections, can help prevent U0673. Ensuring your vehicle's software is updated and inspecting transmission components periodically can also reduce the risk.
What is U0673?
The diagnostic trouble code (DTC) U0673 indicates a communication error between the Engine Control Module (ECM) and the Transmission Control Module (TCM). This error typically arises when the ECM cannot receive data from the TCM, which can cause significant issues in vehicle performance and drivability. For instance, if your vehicle is experiencing U0673, you may notice erratic shifting, reduced power, or even a complete inability to shift gears. This code is most commonly reported in vehicles like the Chevrolet Silverado from model years 2010 to 2018, but it can also affect other makes and models that utilize similar communication protocols. The root cause can often be traced back to damaged wiring, poor connections, or even a malfunctioning TCM. Understanding this code is crucial because it can lead to more severe transmission problems if left unaddressed. Additionally, ignoring this code may result in increased repair costs down the line as other components may be affected by the communication failure.
System: U - Network (Communication, CAN Bus)
Symptoms
Common symptoms when U0673 is present:
- Check engine light stays on constantly, indicating a persistent issue that needs addressing.
- Transmission may slip or hesitate during gear changes, leading to a rough driving experience.
- Fuel economy decreased by 10-20%, as the vehicle struggles to maintain optimal performance.
- Unusual engine behavior, such as stalling or sudden acceleration, may occur due to communication failures.
- In some cases, the vehicle may enter 'limp mode' to protect the engine and transmission, limiting speed and power.
Possible Causes
Most common causes of U0673 (ordered by frequency):
- The most common cause of U0673 is damaged wiring or poor connections, with a likelihood of around 60%. This can result from wear and tear or exposure to the elements.
- A faulty Transmission Control Module (TCM) is the second most common cause, which may occur due to overheating or electrical failures. This is a less frequent issue but can lead to costly repairs.
- Preventive maintenance such as regular inspections of electrical connections can help avoid issues with wiring, reducing the likelihood of this code appearing in the future.
- Less common but serious causes include software issues in the ECM or TCM that may require reflashing to restore proper communication.
- A rare cause could be an internal mechanical failure in the transmission itself, which would necessitate a more extensive diagnostic process.
U0673 Repair Costs
Cost Breakdown by Repair Type
Wiring Repair
Repairing or replacing damaged wiring harnesses or connectors.
- Total: $150 - $400
- Success rate: 85%
TCM Replacement
Replacing the Transmission Control Module if it is found to be faulty.
- Total: $300 - $800
- Success rate: 90%
Software Reflash
Reprogramming the ECM or TCM to fix software-related issues.
- Total: $100 - $200
- Success rate: 75%
Money-Saving Tips for U0673
- 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 U0673 Diagnosis Process
Follow these systematic steps to accurately diagnose U0673. 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 or specific diagnostic tools to test suspected components (20-30 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test suspected components (20-30 minutes).
Step 4: Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes)
Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes).
Step 5: Step 5: Road test verification - Drive vehicle under various conditions to confirm repair success (15-20 minutes)
Step 5: Road test verification - Drive 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: Transmission Communication Error in 2015 Chevrolet Silverado
Vehicle: 2015 Chevrolet Silverado 1500, 75,000 miles
Problem: Customer reported that the check engine light was on, and the transmission was hesitating during shifts.
Diagnosis: Diagnostic scan revealed U0673. A visual inspection showed frayed wiring near the transmission.
Solution: Repaired the damaged wiring and cleared the codes. Conducted a road test to confirm the fix.
Cost: $250 (including parts and labor)
Result: Customer reported smooth shifting and no check engine light after the repair.
Case Study 2: Faulty TCM in 2017 GMC Sierra
Vehicle: 2017 GMC Sierra 1500, 50,000 miles
Problem: Customer experienced erratic shifting and poor acceleration.
Diagnosis: U0673 was confirmed, and testing indicated a faulty TCM.
Solution: Replaced the TCM and updated the software. Conducted thorough testing post-repair.
Cost: $600 (including parts and labor)
Result: Vehicle performance improved significantly, with no further issues reported.