Engine-Codes.com
Engine-Codes – Generic – U1702

U1702 Code - Transmission Control Module Communication Error

Quick Answer

The U1702 code indicates a communication error between the transmission control module (TCM) and other control modules in the vehicle. Common causes include Faulty transmission control moduleWiring issues or damaged connectorsSoftware glitches in the TCMFaulty sensors affecting communication. 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
U1702 indicates Transmission Control Module Communication Error.
Common causes
Common causes include Faulty transmission control moduleWiring issues or damaged connectorsSoftware glitches in the TCMFaulty sensors affecting communication.
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.
What is this?
Table of contents Created and updated by William Orellana on Jun 03, 2026
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code U1702 Description

The U1702 code indicates a communication error between the transmission control module (TCM) and other control modules in the vehicle. This can lead to various performance issues, including erratic shifting, loss of power, and even complete transmission failure if not addressed. The TCM relies on data from other modules to make informed decisions about shifting and engine performance. Ignoring this code can result in long-term damage to the transmission system, as it may operate under incorrect parameters. Additionally, the vehicle may enter a 'limp mode' to protect itself, which can severely limit driving capabilities. It's crucial to diagnose the underlying issue, which may involve checking wiring, connectors, and the TCM itself to ensure proper communication is restored.
OBDII Code U1702 - Transmission Control Module Communication Error
U1702 Code - Transmission Control Module Communication Error

Common Causes of U1702

  1. Faulty transmission control module
  2. Wiring issues or damaged connectors
  3. Software glitches in the TCM
  4. Faulty sensors affecting communication

Symptoms of U1702

  1. Erratic shifting
  2. Loss of power during acceleration
  3. Transmission slipping
  4. Vehicle entering limp mode

How to Fix U1702

  1. Inspect and repair wiring and connectors
  2. Replace faulty transmission control module
  3. Update or reprogram TCM software
  4. Test and replace faulty sensors

Cost to Fix U1702

Repairing a U1702 code can vary significantly based on the underlying issue. Typical costs for parts and labor can range from $150 to $1,200. For example, replacing a transmission control module may cost between $300 and $800, while wiring repairs could be less expensive. Labor rates typically range from $80 to $150 per hour, depending on the shop type and location. Dealerships tend to charge more, while independent shops may offer lower rates. Always consider the specific make, model, and engine type when estimating repair costs.

Need more information about the U1702 code?

Need more information on how to fix the U1702 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1702 code diagnosed by a professional: Find a repair shop in your area

Code U1702 Information for Specific Makes

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 U1702 Code

No Frequently Asked Questions about U1702 Code found.

Discuss the causes and fixes for U1702 OBDII Code

Submit a New Comment

Code U1702 comments

No comments found for this page.