What does it mean if my Chevrolet Silverado 1500 is displaying error code U0073?

Chevrolet Silverado 1500 T1XX (2019-2023)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: U0073

3 min read

598 words

Problem Statement

Learn about error code U0073 in your Chevrolet Silverado 1500, its symptoms, diagnostic steps, and repair instructions to restore communication within the vehicle's control modules.

Error Code

U0073

Affected Component

Control Module Communication Bus 'A'

Estimated Time

2-4 hours

Symptoms

•Check engine light or other warning indicators on the dashboard may illuminate
•Malfunctioning features that rely on electronic control modules
•Power windows, door locks, or other electronic components may become erratic or stop working
•The vehicle may exhibit poor performance or unresponsive throttle

Diagnostic Steps

1
Visual Inspection: Check for any obvious signs of damage to the wiring harness
2
Check Battery Voltage: Ensure the vehicle battery is fully charged
3
Use a professional-grade OBD-II scanner to read the error codes
4
Identify the control modules involved in the CAN
5
Inspect all connectors related to the identified modules
6
Use a multimeter to measure the voltage on the CAN bus wires

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II Scanner
•Multimeter
•Wiring diagram for the specific model
•Basic hand tools (screwdrivers, socket set, etc.)
•Electrical contact cleaner

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Symptoms

•Check engine light or other warning indicators on the dashboard may illuminate

•Malfunctioning features that rely on electronic control modules

•Power windows, door locks, or other electronic components may become erratic or stop working

•The vehicle may exhibit poor performance or unresponsive throttle

Diagnostic Steps

1
Visual Inspection: Check for any obvious signs of damage to the wiring harness
2
Check Battery Voltage: Ensure the vehicle battery is fully charged
3
Use a professional-grade OBD-II scanner to read the error codes
4
Identify the control modules involved in the CAN
5
Inspect all connectors related to the identified modules
6
Use a multimeter to measure the voltage on the CAN bus wires

Solution

Understanding Error Code U0073

The error code U0073 indicates a communication issue within the vehicle's controller area network (CAN), specifically relating to the Control Module Communication Bus 'A' High. This means that one of the control modules on the vehicle is unable to communicate effectively with the others, leading to potential issues in vehicle functionality.

Common Symptoms

Warning Lights: Check engine light or other warning indicators on the dashboard may illuminate.
Communication Issues: Malfunctioning features that rely on electronic control modules, such as advanced safety features, infotainment systems, or stability control.
Unresponsive Vehicle Functions: Power windows, door locks, or other electronic components may become erratic or stop working.
Inconsistent Performance: The vehicle may exhibit poor performance or unresponsive throttle.

Step 1: Initial Inspection

Visual Inspection: Check for any obvious signs of damage to the wiring harness, especially near connectors and modules.
Check Battery Voltage: Ensure the vehicle battery is fully charged (12.4 volts or higher) as low voltage can cause communication errors.

Step 2: Scan for Codes

OBD-II Scanner: Use a professional-grade OBD-II scanner to read the error codes. Look for any additional codes that might be present alongside U0073.

Step 3: Inspect Network Connections

Locate Modules: Identify the control modules involved in the CAN. Common modules include the Engine Control Module (ECM), Transmission Control Module (TCM), Body Control Module (BCM), and others.
Check Connectors: Inspect all connectors related to the identified modules. Disconnect and reconnect them to ensure a proper connection.

Step 4: Measure Voltage on the CAN Bus

Multimeter: Use a multimeter to measure the voltage on the CAN bus wires (typically the CAN High and CAN Low).
- Expected Values: CAN High should typically read around 2.5V when the bus is idle, and CAN Low should be the inverse. While the vehicle is running, these values may vary but should remain within the specified voltage range.

Tools Required

OBD-II Scanner
Multimeter
Wiring diagram for the specific model (to identify module locations and CAN wiring)
Basic hand tools (screwdrivers, socket set, etc.)
Electrical contact cleaner

Repair Instructions

Step 1: Address Wiring Issues

Repair or Replace Damaged Wires: If any damaged wires are found during the visual inspection, repair or replace them.
Clean Connectors: If corrosion is present, use electrical contact cleaner to clean the connectors and ensure a good connection.

Step 2: Replace Faulty Modules

Testing Each Module: If communication issues persist, you may need to test each control module individually.
- Swap Modules: If you have access to known good modules, try swapping them to see if the issue resolves.

Step 3: Clear Codes and Test Drive

Clear Error Codes: Use the OBD-II scanner to clear the U0073 code and any other codes that were stored.
Test Drive: Take the vehicle for a test drive to ensure that the check engine light does not reappear and that all functions are operating normally.

Step 4: Recheck Communication

Re-scan for Codes: After the test drive, check for any new codes or if U0073 returns. If it does, further diagnosis of the communication network may be necessary.

Conclusion

Error code U0073 on your Chevrolet Silverado 1500 indicates a communication issue within the vehicle's control modules. By following the diagnostic steps and performing the necessary repairs, you can restore proper communication and functionality to your vehicle's systems. If the problem persists after these steps, further investigation or professional assistance may be required.