AutoCodes – GMC – U0402 GMC

U0402 GMC Code - Invalid Data Received From Transmission Control Module

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. 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: U0402 GMC indicates Invalid Data Received From 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 1,876

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 Apr 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0402 GMC Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. Some devices are constantly receiving information from other devices through serial data communication network. The invalid data Diagnostic Trouble Code (DTC) will be set when a receiving device detects a discrepancy in the information it receives from the Transmission Control Module (TCM) causing its integrity to be questioned.

OBDII Code U0402 GMC - Invalid Data Received From Transmission Control Module - AutoCodes.com — U0402 GMC Code - Invalid Data Received From Transmission Control Module

What does this mean?

What are the Possible Causes of the DTC U0402 GMC?

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

How to Fix the DTC U0402 GMC?

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 U0402 GMC 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 U0402 GMC Code

1. What are common symptoms of OBDII code U0402 in a GMC vehicle?

- Common symptoms include issues with shifting gears, transmission slipping, harsh shifting, and illuminated warning lights on the dashboard.

2. What does OBDII code U0402 in a GMC indicate?

- This code indicates that the engine control module (ECM) has detected invalid data being received from the transmission control module (TCM).

3. What are potential causes of OBDII code U0402 in a GMC?

- Potential causes include faulty wiring or connectors between the ECM and TCM, a malfunctioning TCM, software issues, or a communication network problem.

4. How can I diagnose the source of OBDII code U0402 in my GMC?

- Diagnosis typically involves checking the wiring and connectors between the ECM and TCM, performing a scan tool diagnosis to assess communication between modules, and inspecting for any software issues.

5. Can I drive my GMC with OBDII code U0402 present?

- It is not recommended to drive the vehicle with this code present, as it can lead to further transmission issues and potential safety hazards.

6. Is it safe to continue driving if the symptoms of OBDII code U0402 disappear on their own?

- Even if the symptoms disappear temporarily, it is still advised to have the issue diagnosed and repaired to prevent any potential long-term damage to the transmission system.

7. How can I repair OBDII code U0402 in my GMC?

- Repair options may include fixing any wiring or connector issues, replacing the TCM if faulty, updating software, or addressing any communication network problems.

8. Can a DIY enthusiast fix OBDII code U0402, or should I seek professional help?

- Depending on your experience and expertise, some simple checks like inspecting wiring connections can be done by a DIY enthusiast. However, more complex repairs may require professional help.

9. Will resetting the OBDII code U0402 clear the issue in my GMC?

- Simply resetting the code may temporarily clear the issue, but it is important to diagnose and address the root cause to prevent the code from reappearing.

10. How much can I expect to pay to repair OBDII code U0402 in a GMC?

- Repair costs can vary depending on the exact cause of the issue and whether you go to a dealership or an independent mechanic. It is recommended to get a few quotes for comparison.