U0020 Code - Low Speed CAN Bus
Quick Answer
Devices connected to the General Motors Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include If other codes are present, diagnose other codes first, Faulty Control Module, Control Module harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- U0020 indicates Low Speed CAN Bus.
- Common causes
- Common causes include If other codes are present, diagnose other codes first, Faulty Control Module, Control Module harness is open or shorted.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code U0020 Description
What are the Possible Causes of the DTC U0020?
- If other codes are present, diagnose other codes first
- Faulty Control Module
- Control Module harness is open or shorted
- Control Module circuit poor electrical connection
How to Fix the DTC U0020?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the U0020 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the U0020 code?
Need more information on how to fix the U0020 code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the U0020 code diagnosed by a professional: Find a repair shop in your area
Information for Specific Makes
- U0020 Buick — Low Speed CAN Bus
- U0020 Cadillac — Low Speed CAN Bus
- U0020 Chevrolet — Low Speed CAN Bus
- U0020 GMC — Low Speed CAN Bus
Frequently Asked Questions about U0020 Code
1. What are the common symptoms of an OBDII code U0020 (Low Speed CAN Bus)?
- Common symptoms include issues with the vehicle's communication network, such as intermittent or complete loss of communication between control modules.
2. What are the possible causes of an OBDII code U0020?
- The code U0020 can be caused by damaged wiring, loose connections, faulty control modules, or a malfunctioning CAN bus system.
3. How can I diagnose the OBDII code U0020?
- Diagnosing the code may involve using a scan tool to check for trouble codes, inspecting the wiring and connectors related to the CAN bus system, and performing a network communication test.
4. Can a faulty sensor trigger the OBDII code U0020?
- Yes, a faulty sensor or control module connected to the Low Speed CAN Bus network can trigger the U0020 code.
5. What repairs are typically needed to fix the OBDII code U0020?
- Repairs may include repairing or replacing damaged wiring, ensuring proper connections, replacing faulty control modules, and addressing any issues with the CAN bus network.
6. Is it safe to continue driving with an OBDII code U0020 present?
- It is generally not recommended to drive with the U0020 code present, as it can affect the vehicle's communication system and potentially lead to other issues.
7. How do I reset the OBDII code U0020 after making repairs?
- After making necessary repairs, you can reset the code using an OBDII scan tool or by disconnecting the vehicle's battery for a few minutes.
8. Can extreme weather conditions cause the OBDII code U0020 to appear?
- Extreme weather conditions can potentially affect the CAN bus system and lead to the U0020 code, especially if there are existing wiring or connection issues.
9. Will the check engine light always come on with the OBDII code U0020?
- The check engine light may illuminate when the U0020 code is triggered, but it is not always guaranteed. It's important to diagnose the issue even if the light is not on.
10. Are there any preventative measures to avoid the OBDII code U0020 from reoccurring?
- Regularly inspecting and maintaining the vehicle's wiring, connectors, and control modules can help prevent the U0020 code from reoccurring.
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