AutoCodes – GMC – U1888 GMC

U1888 GMC Code - Hybrid Control Module Lost Communication With Energy Storage Control Module

Quick Answer

Modules connected to the class 2 and high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Energy Storage Control Module (ESCM), Energy Storage Control Module harness is open or shorted, Energy Storage 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: U1888 GMC indicates Hybrid Control Module Lost Communication With Energy Storage Control Module.
Common causes: Common causes include Faulty Energy Storage Control Module (ESCM), Energy Storage Control Module harness is open or shorted, Energy Storage 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 1,429

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 Jun 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1888 GMC Description

Modules connected to the class 2 and high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The Diagnostic Trouble Code (DTC) is reported on a class 2 link to the scan tool by Powertrain Control Module (PCM) even if they may be set by different modules. The DTC will set when a node alive message has not been received from an identified module within the last 5 seconds after establishing class 2 serial data communication, or a supervised high-speed GMLAN message has not been received.

OBDII Code U1888 GMC - Hybrid Control Module Lost Communication With Energy Storage Control Module - AutoCodes.com — U1888 GMC Code - Hybrid Control Module Lost Communication With Energy Storage Control Module

What does this mean?

What are the Possible Causes of the DTC U1888 GMC?

Faulty Energy Storage Control Module (ESCM)
Energy Storage Control Module harness is open or shorted
Energy Storage Control Module circuit poor electrical connection
Faulty Hybrid Control Module (HCM)

How to Fix the DTC U1888 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 U1888 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 U1888 GMC Code

1. What does the OBDII code U1888 mean on a GMC?

The U1888 code indicates that the Hybrid Control Module (HCM) has lost communication with the Energy Storage Control Module (ESCM).

2. What are the common symptoms of code U1888 on a GMC vehicle?

Common symptoms include a check engine light, reduced hybrid system performance, inability to charge the hybrid battery, or the vehicle operating in reduced power mode.

3. What causes the U1888 code to appear in a GMC?

This code is often caused by faulty wiring, poor electrical connections, a failed Hybrid Control Module, a malfunctioning Energy Storage Control Module, or software issues.

4. Can I drive my GMC with the U1888 code active?

While the vehicle may still operate, driving with this code active can lead to reduced power and hybrid system functionality, and itâ€™s recommended to address the issue promptly.

5. How do I diagnose the U1888 code on my GMC?

Start by using an advanced scan tool to check for related codes, inspect the wiring and connectors between the HCM and ESCM, and test the modules for proper operation.

6. What repairs might fix the U1888 code on a GMC?

Possible repairs include repairing or replacing damaged wiring, cleaning or re-securing electrical connectors, reprogramming the modules, or replacing a faulty HCM or ESCM.

7. Does the U1888 code require module reprogramming?

In some cases, reprogramming the Hybrid Control Module or Energy Storage Control Module with the latest software updates can resolve the issue.

8. Can a low hybrid battery cause the U1888 code?

A low or faulty hybrid battery might trigger communication issues between the modules, so itâ€™s worth checking the batteryâ€™s condition.

9. How much does it cost to fix the U1888 code on a GMC?

The cost depends on the root cause, ranging from $100â€“$300 for wiring repairs to over $1,000 for module replacements.

10. What tools are needed to troubleshoot the U1888 code on a GMC?

Youâ€™ll need an advanced OBDII scan tool capable of reading hybrid system codes, a multimeter for electrical testing, and possibly manufacturer-specific diagnostic tools.