AutoCodes – Toyota – U1104 2016 Toyota RAV4

U1104 2016 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 2016 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 295

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 2016 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 2016 Toyota RAV4 - Lost Communication with Driving Support ECU - AutoCodes.com — U1104 2016 Toyota RAV4 Code - Lost Communication with Driving Support ECU

What does this mean?

What are the Possible Causes of the DTC U1104 2016 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 2016 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 2016 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 2016 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 2016 Toyota RAV4 Code

1. What are the common symptoms of OBDII code U1104 in a 2016 Toyota RAV4?

The common symptoms include issues with the vehicle's driving support systems, such as adaptive cruise control, lane-keeping assist, or collision warning not functioning properly.

2. What can cause the OBDII code U1104 "Lost Communication with Driving Support ECU" in a 2016 Toyota RAV4?

The code U1104 can be triggered by a faulty driving support ECU, damaged wiring or connectors, software glitches, or communication network issues in the vehicle.

3. How can I diagnose the cause of the U1104 code in my 2016 Toyota RAV4?

Diagnosing the U1104 code typically involves checking the connections to the driving support ECU, inspecting the wiring for damage, and using a diagnostic scanner to determine the specific communication issue.

4. Can I still drive my 2016 Toyota RAV4 with the U1104 code present?

It is generally safe to drive the vehicle with the U1104 code, but it is recommended to have the issue diagnosed and repaired as soon as possible to ensure the proper functioning of driving support systems.

5. How can I repair the U1104 code in my 2016 Toyota RAV4?

Repairing the U1104 code may involve resetting the ECU, repairing or replacing damaged wiring or connectors, updating software, or replacing the driving support ECU if necessary.

6. Is it possible to clear the U1104 code in a 2016 Toyota RAV4 without fixing the underlying issue?

While clearing the code with a diagnostic scanner may temporarily turn off the warning light, it is crucial to address the root cause of the communication error to prevent the code from reappearing.

7. Will disconnecting the battery reset the U1104 code in my 2016 Toyota RAV4?

Disconnecting the battery may reset the ECU and clear the code temporarily, but if the underlying issue causing the communication error is not resolved, the code is likely to return.

8. How much does it cost to repair the U1104 code in a 2016 Toyota RAV4?

The cost of repairing the U1104 code can vary depending on the specific cause of the communication error, the extent of the repair needed, and whether any components need replacement. It is recommended to consult a professional for an accurate estimate.

9. Can a DIY enthusiast fix the U1104 code in a 2016 Toyota RAV4?

While some basic troubleshooting steps can be taken by DIY enthusiasts, diagnosing and repairing the U1104 code often requires specialized tools, technical knowledge, and expertise, so it is advisable to seek professional help.

10. How common is the U1104 code "Lost Communication with Driving Support ECU" in 2016 Toyota RAV4 vehicles?

The U1104 code is relatively uncommon but can occur in 2016 Toyota RAV4 models due to various factors such as electronic system failures, wiring issues, software glitches, or component malfunctions.