AutoCodes – Toyota – U1104 2017 Toyota RAV4

U1104 2017 Toyota RAV4 Code - Lost Communication with Driving Support ECU

Quick Answer

The Controller Area Network (CAN) is a standard bus system in vehicles that enables the connection of automotive devices without the need for a host computer. Common causes include Faulty Controller Area Network (CAN) Communication System, Faulty Driving Support ECU, Driving Support ECU 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: U1104 2017 Toyota RAV4 indicates Lost Communication with Driving Support ECU.
Common causes: Common causes include Faulty Controller Area Network (CAN) Communication System, Faulty Driving Support ECU, Driving Support ECU 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.

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Code Popularity 367

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 27, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U1104 2017 Toyota RAV4 Description

The Controller Area Network (CAN) is a standard bus system in vehicles that enables the connection of automotive devices without the need for a host computer. The exchange of operating information and commands among devices is facilitated by pre-programmed information about the required message exchange on the serial data circuits. Communication is carried out using two dedicated wires, known as CAN high and CAN low, with both lines carrying 2.5V when the CAN bus is in idle mode. During the transmission of data bits, the CAN high line increases to 3.75V while the CAN low drops to 1.25V, creating 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 periodic message from the Driving Support ECU has not been received.

OBDII Code U1104 2017 Toyota RAV4 - Lost Communication with Driving Support ECU - AutoCodes.com — U1104 2017 Toyota RAV4 Code - Lost Communication with Driving Support ECU

What does this mean?

What are the Possible Causes of the DTC U1104 2017 Toyota RAV4?

Faulty Controller Area Network (CAN) Communication System
Faulty Driving Support ECU
Driving Support ECU harness is open or shorted
Driving Support ECU circuit poor electrical connection

How to Fix the DTC U1104 2017 Toyota RAV4?

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 does this mean?

Code Tech Notes

When there are problems with the way different systems in a vehicle communicate with each other using a technology called Controller Area Network (CAN) communication, Diagnostic Trouble Codes (DTC) are displayed. These codes can be caused by issues with the main bus or branch of the communication network, or with the Electronic Control Units (ECUs) and sensors that make up the different systems. If you see code for both the CAN communication problems and internal or power source problems at the same time, you should focus on fixing the internal or power source problems first.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U1104 2017 Toyota RAV4 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 U1104 2017 Toyota RAV4 code?

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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 U1104 2017 Toyota RAV4 Code

1. What does the OBDII code U1104 mean for my 2017 Toyota RAV4?

The U1104 code indicates a communication error with the Driving Support ECU in your RAV4.

2. What are the common symptoms of U1104 code in a 2017 Toyota RAV4?

Common symptoms include loss of driving assistance features like lane departure warning or adaptive cruise control, as well as potential illumination of the check engine light.

3. What are the possible causes of the U1104 code in a 2017 Toyota RAV4?

Causes can include damaged wiring or connectors, a faulty Driving Support ECU, software issues, or a communication network problem within the vehicle.

4. How can I diagnose the U1104 code in my 2017 Toyota RAV4?

Diagnosis typically involves inspecting the wiring and connectors related to the Driving Support ECU, checking for any visible damages, and using a diagnostic scanner to analyze the communication network.

5. Can I drive my 2017 Toyota RAV4 with the U1104 code?

It is generally safe to drive the vehicle with the U1104 code, but you may experience a loss of certain driving assistance features until the issue is resolved.

6. How do I repair the U1104 code in my 2017 Toyota RAV4?

Repair methods can vary depending on the specific cause, but common solutions include repairing or replacing damaged wiring, connectors, or the Driving Support ECU.

7. Will resetting the U1104 code make it go away permanently?

Simply clearing the code may not resolve the underlying issue causing the communication error. It is important to diagnose and address the root cause of the problem for a permanent fix.

8. Is the U1104 code in a 2017 Toyota RAV4 a serious problem?

While it may not pose an immediate safety risk, addressing the U1104 code is important to ensure the proper functioning of driving assistance systems and to prevent potential future issues.

9. Can I fix the U1104 code in my 2017 Toyota RAV4 myself?

Depending on your level of automotive expertise, you may be able to address simpler causes such as loose connectors. However, more complex issues may require professional diagnosis and repair.

10. How much does it cost to fix the U1104 code in a 2017 Toyota RAV4?

The cost of repair can vary based on the specific cause of the U1104 code. It is recommended to obtain quotes from reputable auto repair shops for an accurate estimate.