Quick Answer
U0873 means: U0873 indicates a communication error between the vehicle's control modules, specifically with the transmission control module.
Can I drive with U0873? It's advisable to diagnose and address this issue promptly to avoid serious transmission problems.
Common Questions
What does U0873 mean and how does it affect my car?
The U0873 code indicates a communication failure between your vehicle's control modules, particularly involving the transmission control module. This can lead to various performance issues, including erratic shifting and reduced power, which can affect your driving experience and safety.
What are the most common causes of U0873 and how much does it cost to fix?
Common causes include damaged wiring (60% likelihood) and a malfunctioning TCM. Repair costs can range from $150 for wiring repairs to $1,500 for a TCM replacement, depending on the severity.
Can I drive my car with U0873 or should I stop immediately?
While you may be able to drive the car, it is not advisable. Ignoring the U0873 code can lead to severe transmission issues and safety risks. It's best to diagnose and fix it as soon as possible.
How can I diagnose U0873 myself using GeekOBD APP?
Using the GeekOBD APP, you can scan for DTCs, view freeze frame data, and monitor live vehicle parameters. This helps you understand the context of the U0873 code and narrow down potential issues.
What vehicles are most commonly affected by U0873?
This code is often found in various GM models, including the Chevrolet Silverado and GMC Sierra from 2010 to 2015, as well as some Cadillac and Buick models. Always check for recalls or TSBs related to your vehicle.
How can I prevent U0873 from happening again?
Regular maintenance, including inspecting wiring and connectors for wear and corrosion, can help prevent U0873 from recurring. Keeping your vehicle's software updated is also essential.
What is U0873?
The U0873 diagnostic trouble code indicates a communication issue between two or more control modules within the vehicle's network. Specifically, this code signifies that the vehicle's control module has received an invalid message from the transmission control module (TCM). This issue can affect a range of vehicles but is particularly common in various General Motors models from 2010 to 2015, such as the Chevrolet Silverado and GMC Sierra. When the U0873 code is triggered, it can lead to issues such as erratic shifting, a lack of response from the vehicle's transmission, or even a complete failure to communicate with the TCM. This can result in the check engine light illuminating on your dashboard, and if left unresolved, it could lead to more significant transmission problems over time, leading to costly repairs. Addressing this issue promptly is crucial to maintaining your vehicle's performance and safety. Regular inspections of the vehicle’s wiring and connectors, especially in older vehicles, can help catch such issues before they escalate.
System: U - Network (Communication, CAN Bus)
Symptoms
Common symptoms when U0873 is present:
- The check engine light may stay on constantly, indicating a problem in the vehicle's control system.
- Drivers may notice erratic shifting or delayed response when changing gears, making the vehicle feel sluggish.
- Fuel economy may decrease by 10-15%, resulting in increased trips to the gas station and higher overall costs.
- You may experience a reduction in overall vehicle performance, with potential stalling or hesitation during acceleration.
- In severe cases, the vehicle may enter 'limp mode', which restricts power to prevent damage to the transmission.
Possible Causes
Most common causes of U0873 (ordered by frequency):
- The most common cause of U0873 is damaged wiring or poor connections within the vehicle's electrical system, with a likelihood of about 60%. This can often be traced back to corrosion or wear and tear.
- A second common cause is a malfunctioning transmission control module itself, which can lead to a failure in communication between the TCM and the vehicle's main computer.
- Faulty software in the vehicle's control modules can also trigger this code, especially in models that have undergone updates or recalls; keeping your software current can help prevent this.
- Less common but serious causes include a failing powertrain control module (PCM) or other integral components that influence vehicle communication.
- A rare cause could be a complete failure of the vehicle’s communication network, which could require extensive diagnostic work to identify and repair.
U0873 Repair Costs
Cost Breakdown by Repair Type
Wiring and Connector Repair
Repair or replacement of damaged wiring or connectors in the vehicle's communication network.
- Total: $150 - $500
- Success rate: 85%
Transmission Control Module Replacement
Replacing a faulty transmission control module that may be causing the communication error.
- Total: $400 - $1,500
- Success rate: 90%
Money-Saving Tips for U0873
- 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 U0873 Diagnosis Process
Follow these systematic steps to accurately diagnose U0873. 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 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: Wiring Repair on 2014 Chevrolet Silverado
Vehicle: 2014 Chevrolet Silverado 1500, 80,000 miles
Problem: Customer reported check engine light on and erratic transmission shifting.
Diagnosis: After scanning with the GeekOBD APP, U0873 was identified. Visual inspection revealed damaged wiring under the driver's seat.
Solution: Repaired the damaged wiring and cleared the codes.
Cost: $200
Result: The check engine light turned off, and normal shifting was restored.
Case Study 2: TCM Replacement in 2013 GMC Sierra
Vehicle: 2013 GMC Sierra 1500, 95,000 miles
Problem: Vehicle entered limp mode with U0873 code present.
Diagnosis: Diagnostic tests confirmed that the transmission control module was not communicating properly.
Solution: Replaced the faulty TCM and updated the vehicle’s software.
Cost: $1,200
Result: Vehicle performance improved, and no further issues were reported.