AutoCodes – Toyota – U0101 2015 Toyota RAV4

U0101 2015 Toyota RAV4 Code - Lost Communication with Transmission Control Module

Quick Answer

The Transmission Control Module (TCM) and Engine Control Module (ECM) perform 2-way communications with each other via the Controller Area Network (CAN). Common causes include Faulty Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission Control Module circuit poor electrical connection. 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: U0101 2015 Toyota RAV4 indicates Lost Communication with Transmission Control Module .
Common causes: Common causes include Faulty Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission Control Module circuit poor electrical connection.
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)

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Table of contents Created and updated by William Orellana on Mar 23, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0101 2015 Toyota RAV4 Description

The Transmission Control Module (TCM) and Engine Control Module (ECM) perform 2-way communications with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine rpm, required engine torques, warning indicators in the combination meter, DTCs, and other data. The ECM sends signals to the TCM concerning engine rpm, opening angles of the throttle valve, temperature of intake air, the temperature of engine coolant, engine torques, and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL, and set a DTC.

OBDII Code U0101 2015 Toyota RAV4 - Lost Communication with Transmission Control Module - AutoCodes.com — U0101 2015 Toyota RAV4 Code - Lost Communication with Transmission Control Module

What does this mean?

What are the Possible Causes of the DTC U0101 2015 Toyota RAV4?

Faulty Transmission Control Module (TCM)
Transmission Control Module harness is open or shorted
Transmission Control Module circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC U0101 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U0101 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 U0101 2015 Toyota RAV4 Code

What does the OBDII code U0101 mean for a 2015 Toyota RAV4?

U0101 indicates a loss of communication with the Transmission Control Module (TCM), which can affect vehicle performance and shifting.

What are common symptoms of the U0101 code in a 2015 Toyota RAV4?

Common symptoms include harsh or erratic shifting, poor acceleration, the transmission failing to engage, and the check engine light being illuminated.

What can cause the U0101 code in a 2015 Toyota RAV4?

Causes can include faulty wiring, a defective Transmission Control Module, a blown fuse, or issues with the vehicle's engine control module (ECM).

How can I diagnose the U0101 code in my 2015 Toyota RAV4?

Start by visually inspecting the wiring and connectors related to the TCM for damage. Then, use an OBDII scanner to check for other related codes and perform a continuity test on the TCM circuit.

What repairs are commonly needed for a U0101 code?

Repairs may involve fixing or replacing damaged wiring, replacing a faulty TCM, or reprogramming the TCM to restore communication.

Is it safe to drive a 2015 Toyota RAV4 with the U0101 code?

It is not recommended to drive the vehicle as it may lead to transmission issues and could compromise safety due to erratic shifting.

Can a low battery cause the U0101 code in a 2015 Toyota RAV4?

Yes, a low or weak battery can cause electrical issues that may lead to communication problems with the TCM, triggering the U0101 code.

How much will it cost to fix the U0101 code in a 2015 Toyota RAV4?

Repair costs can vary widely; expect to pay anywhere from $100 for minor wiring repairs to over $1,000 if the TCM needs replacement.

Should I reset the code after repairs for U0101 on my 2015 Toyota RAV4?

Yes, after completing repairs, resetting the code and taking the vehicle for a test drive is advisable to ensure the issue is resolved and that the code does not return.