AutoCodes – Toyota – U0140 2015 Toyota RAV4

U0140 2015 Toyota RAV4 Code - Lost Communication with Main Body 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 Main Body ECU, Main Body 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: U0140 2015 Toyota RAV4 indicates Lost Communication with Main Body ECU.
Common causes: Common causes include Faulty Controller Area Network (CAN) Communication System, Faulty Main Body ECU, Main Body 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 270

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 26, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U0140 2015 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 Main Body ECU has not been received.

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OBDII Code U0140 2015 Toyota RAV4 - Lost Communication with Main Body ECU - AutoCodes.com — U0140 2015 Toyota RAV4 Code - Lost Communication with Main Body ECU

What does this mean?

What are the Possible Causes of the DTC U0140 2015 Toyota RAV4?

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

How to Fix the DTC U0140 2015 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 U0140 2015 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 U0140 2015 Toyota RAV4 Code

1. What does the OBDII code U0140 mean for a 2015 Toyota RAV4?

The U0140 code indicates a communication issue between the vehicle's main body electronic control unit (ECU) and other control modules.

2. What are some common symptoms of the U0140 code in a 2015 Toyota RAV4?

Common symptoms include illuminated warning lights on the dashboard, loss of certain electrical functions like power windows or door locks, and possible drivability issues.

3. What are possible causes of the U0140 code in a 2015 Toyota RAV4?

Possible causes of the U0140 code include damaged wiring or connectors, a malfunctioning main body ECU, software issues, or a fault in another control module.

4. How can I diagnose the U0140 code in my 2015 Toyota RAV4?

Diagnosing the U0140 code typically involves using a diagnostic scanner to retrieve the code, checking for any other related codes, inspecting wiring and connectors, and testing the main body ECU and other relevant modules.

5. Can I still drive my 2015 Toyota RAV4 with a U0140 code?

It is not recommended to drive the vehicle with a U0140 code present, as it may lead to further electrical issues or potential safety hazards. It's best to have the issue diagnosed and repaired promptly.

6. How can I repair the U0140 code in my 2015 Toyota RAV4?

Repairing the U0140 code may involve repairing or replacing damaged wiring or connectors, reprogramming the main body ECU or other control modules, or replacing faulty components as needed.

7. Can a DIY enthusiast fix the U0140 code in a 2015 Toyota RAV4?

While some basic diagnosis steps can be performed by DIY enthusiasts, resolving the U0140 code may require specialized tools and knowledge, so it's recommended to consult a professional technician for proper repair.

8. How much does it cost to fix the U0140 code in a 2015 Toyota RAV4?

The cost of fixing the U0140 code can vary depending on the underlying cause of the issue, the extent of repairs needed, and labor rates in your area. It's best to get a diagnostic assessment from a qualified mechanic for an accurate estimate.

9. Will resetting the trouble codes make the U0140 code disappear in my 2015 Toyota RAV4?

Resetting the trouble codes may temporarily clear the U0140 code, but if the underlying issue is not addressed, the code is likely to reappear once the vehicle is driven and the communication problem persists.

10. How can I prevent the U0140 code from appearing in my 2015 Toyota RAV4 in the future?

To prevent the U0140 code from reoccurring, it's essential to address any underlying communication issues promptly, perform regular maintenance on the vehicle's electrical system, and address any warning signs promptly to avoid potential issues.