AutoCodes – Toyota – U1114 Toyota

U1114 Toyota Code - Lost Communication with Main Switch Module

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 Switch Module, Main Switch Module 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: U1114 Toyota indicates Lost Communication with Main Switch Module.
Common causes: Common causes include Faulty Controller Area Network (CAN) Communication System, Faulty Main Switch Module, Main Switch Module 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 472

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 28, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U1114 Toyota 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 Switch Module has not been received.

OBDII Code U1114 Toyota - Lost Communication with Main Switch Module - AutoCodes.com — U1114 Toyota Code - Lost Communication with Main Switch Module

What does this mean?

What are the Possible Causes of the DTC U1114 Toyota?

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

How to Fix the DTC U1114 Toyota?

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 U1114 Toyota 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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Information for Specific Toyota Models

U1114 2013 Toyota RAV4 — Lost Communication with Main Switch Module
U1114 2014 Toyota RAV4 — Lost Communication with Main Switch Module
U1114 2015 Toyota RAV4 — Lost Communication with Main Switch Module
U1114 2016 Toyota RAV4 — Lost Communication with Main Switch Module
U1114 2017 Toyota RAV4 — Lost Communication with Main Switch Module
U1114 2018 Toyota RAV4 — Lost Communication with Main Switch Module

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 U1114 Toyota Code

1. What does the OBDII code U1114 mean on a Toyota?

The U1114 code indicates a "Lost Communication with Main Switch Module," meaning the vehicle's control modules are not receiving signals from the main switch module.

2. What are common symptoms of the U1114 code on a Toyota?

Common symptoms include warning lights on the dashboard, malfunctioning switches or controls, and intermittent electrical issues.

3. What causes the U1114 code to appear on a Toyota?

Causes may include faulty wiring or connectors, a malfunctioning main switch module, or issues with the CAN (Controller Area Network) communication system.

4. Can I drive my Toyota with the U1114 code present?

While the vehicle may still operate, driving with this code is not recommended as it can indicate critical communication issues that may impact safety or performance.

5. How do I diagnose the U1114 code on a Toyota?

Diagnosis involves using an OBDII scanner to confirm the code, inspecting wiring and connectors for damage, and testing the main switch module for proper function.

6. What repairs are needed to fix the U1114 code on a Toyota?

Repairs may include fixing damaged wiring, cleaning or replacing corroded connectors, reprogramming the module, or replacing the main switch module if faulty.

7. Can a dead battery cause the U1114 code on a Toyota?

Yes, a dead or weak battery can disrupt communication between modules and trigger the U1114 code.

8. How much does it cost to fix the U1114 code on a Toyota?

Repair costs vary but can range from $100 for wiring repairs to over $500 if the main switch module needs replacement.

9. Can I clear the U1114 code without fixing the issue?

Clearing the code is possible with a scanner, but it will likely reappear unless the underlying issue is resolved.

10. Does the U1114 code require professional repair, or can I fix it myself?

Simple fixes like reconnecting loose wires can be done by DIYers, but diagnosing and repairing module communication issues often requires professional tools and expertise.