AutoCodes – Generic – U0022

U0022 Code - Low Speed CAN Communication Bus (+) Low

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module. 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: U0022 indicates Low Speed CAN Communication Bus (+) Low.
Common causes: Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module.
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.

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Code Popularity 5,635

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 29, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0022 Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U0022 - Low Speed CAN Communication Bus (+) Low - AutoCodes.com — U0022 Code - Low Speed CAN Communication Bus (+) Low

What does this mean?

What are the Possible Causes of the DTC U0022?

Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s)
Check for more codes
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC U0022?

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 U0022 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 U0022 code?

Need more information on how to fix the U0022 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0022 code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U0022 Code

1. What does OBDII code U0022 indicate?

- Code U0022 indicates an issue with the low-speed Controller Area Network (CAN) communication bus, specifically that the positive signal is lower than expected.

2. What symptoms might I notice if my vehicle has the U0022 error code?

- Symptoms can include the Check Engine Light turning on, various electrical systems malfunctioning, and possible issues with vehicle components that rely on CAN communication for operation, such as stability control and power steering.

3. What could cause the OBDII code U0022 to appear?

- Causes can include damaged wires in the CAN bus, faulty CAN bus resistors, poor electrical connections, or a defective control module.

4. How can I diagnose the cause of code U0022 in my vehicle?

- Diagnosing this error generally requires using a scan tool to monitor CAN bus communications, checking for continuity and resistance in the CAN bus wiring, and inspecting for any physical damage or corrosion in the wiring and connectors.

5. What are the potential risks of ignoring an OBDII code U0022?

- Ignoring this code can lead to increased risk of vehicle performance issues, potential safety hazards due to failure of critical systems like anti-lock brakes or electronic stability control, and further damage to the vehicleâ€™s communication network.

6. Are there any specific repair tips for addressing code U0022 in my vehicle?

- Repair tips include cleaning and securing all ground connections, replacing any damaged or corroded wires, and ensuring that all CAN bus connections are tight and free from corrosion. Also, check the integrity of termination resistors in the CAN network.

7. How urgent is it to address a U0022 error code?

- It is fairly urgent to address this code because it can affect multiple systems that are crucial for safe vehicle operation. Delaying repairs might lead to more serious issues or complete failure of critical systems.

8. Can I drive my car with the U0022 code showing?

- While the car may still be drivable, it is advisable to address the issue as soon as possible. Driving with this code active can lead to unpredictable behavior of the vehicleâ€™s electronic systems, which could compromise safety.