AutoCodes – Toyota – U1104 2013 Toyota RAV4

U1104 2013 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 2013 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 211

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 2013 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 2013 Toyota RAV4 - Lost Communication with Driving Support ECU - AutoCodes.com — U1104 2013 Toyota RAV4 Code - Lost Communication with Driving Support ECU

What does this mean?

What are the Possible Causes of the DTC U1104 2013 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 2013 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 2013 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.

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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 2013 Toyota RAV4 Code

1. What does the OBDII code U1104 on a 2013 Toyota RAV4 indicate?

- The code U1104 signifies "Lost Communication with Driving Support ECU" in the vehicle's onboard diagnostics system.

2. What are the common symptoms of U1104 code in a 2013 Toyota RAV4?

- Common symptoms may include issues with electronic stability control, traction control, or other driving support systems malfunctioning.

3. What are the possible causes of the U1104 code in a 2013 Toyota RAV4?

- Potential causes of the U1104 code include wiring issues, faulty connections, a defective driving support ECU, or a communication network problem.

4. How can I diagnose the U1104 code on my 2013 Toyota RAV4?

- Diagnosing the U1104 code involves checking the wiring and connections related to the driving support ECU, as well as using a diagnostic scanner to analyze the communication network.

5. Can the U1104 code on a 2013 Toyota RAV4 be fixed by resetting the ECU?

- Resetting the ECU may temporarily clear the code, but if the underlying issue causing the communication loss persists, the code is likely to reappear.

6. Is it safe to drive a 2013 Toyota RAV4 with the U1104 code illuminated?

- It is generally not recommended to drive the vehicle with the U1104 code active, as it may affect the proper functioning of critical driving support systems.

7. Are there any simple repairs I can attempt to fix the U1104 code on my 2013 Toyota RAV4?

- Simple repairs like checking and securing the wiring harness connections or ensuring proper grounding can sometimes resolve the U1104 code issue.

8. How much does it typically cost to repair the U1104 code on a 2013 Toyota RAV4?

- The cost of repairing the U1104 code can vary depending on the underlying cause, but it may involve expenses for parts replacement, labor, and diagnostic services.

9. Can a DIY enthusiast fix the U1104 code issue in a 2013 Toyota RAV4?

- While some basic troubleshooting steps can be done by a DIY enthusiast, diagnosing and repairing the U1104 code may require specialized tools and expertise best handled by a professional mechanic.

10. Will ignoring the U1104 code in a 2013 Toyota RAV4 lead to further damage?

- Ignoring the U1104 code can potentially lead to the degradation of driving support system functionality, compromising safety and overall vehicle performance over time.