AutoCodes – Chevrolet – U1842 Chevrolet

U1842 Chevrolet Code - Lost Communication With ECM/PCM

Quick Answer

The system voltage is between 9-16 volts. Common causes include Faulty Engine Control Module (ECM)/Powertrain Control Module (PCM), Engine Control Module /Powertrain Control Module harness is open or shorted, Engine Control Module /Powertrain 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: U1842 Chevrolet indicates Lost Communication With ECM/PCM.
Common causes: Common causes include Faulty Engine Control Module (ECM)/Powertrain Control Module (PCM), Engine Control Module /Powertrain Control Module harness is open or shorted, Engine Control Module /Powertrain 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 1,330

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 Jun 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1842 Chevrolet Description

The system voltage is between 9-16 volts. The vehicle power mode master indicates that the need for serial data communications. The Diagnostic Trouble Code (DTC) will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U1842 Chevrolet - Lost Communication With ECM/PCM - AutoCodes.com — U1842 Chevrolet Code - Lost Communication With ECM/PCM

What does this mean?

What are the Possible Causes of the DTC U1842 Chevrolet?

Faulty Engine Control Module (ECM)/Powertrain Control Module (PCM)
Engine Control Module /Powertrain Control Module harness is open or shorted
Engine Control Module /Powertrain Control Module circuit poor electrical connection

How to Fix the DTC U1842 Chevrolet?

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 U1842 Chevrolet 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.

Need more information about the U1842 Chevrolet code?

Need more information on how to fix the U1842 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1842 Chevrolet code diagnosed by a professional: Find a repair shop in your area

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 U1842 Chevrolet Code

1. What does the OBDII code U1842 for Chevrolet mean?

The U1842 code indicates a communication problem between the vehicle's control module (ECM/PCM) and another module.

2. What are common symptoms of U1842 code on a Chevrolet?

Common symptoms include issues starting the vehicle, reduced engine performance, stalling, and warning lights on the dashboard.

3. What are possible causes of the U1842 code on a Chevrolet?

Potential causes include faulty wiring or connectors, a defective ECM/PCM, software issues, or a malfunctioning communication module.

4. How can I diagnose the U1842 code on my Chevrolet?

Diagnosing the U1842 code typically involves checking the wiring and connectors for damage, ensuring proper power and ground connections, and using a scan tool to communicate with the ECM/PCM.

5. Can I still drive my Chevrolet with the U1842 code present?

It is not recommended to drive the vehicle with the U1842 code active, as it may lead to further damage or safety issues. It's best to address the problem promptly.

6. How can I repair the U1842 code on my Chevrolet?

Repairing the U1842 code may involve repairing or replacing damaged wiring, connectors, or components related to the communication system. In some cases, reprogramming the ECM/PCM may be necessary.

7. Can I reset the U1842 code on my Chevrolet without fixing the underlying issue?

While you can clear the code with a scan tool, it's important to address the root cause of the communication problem to prevent the code from reappearing.

8. How much does it cost to fix the U1842 code on a Chevrolet?

The cost of fixing the U1842 code can vary depending on the exact cause of the issue and the labor rates in your area. It's best to consult a professional mechanic for an accurate estimate.

9. Are there any DIY tips for addressing the U1842 code on my Chevrolet?

DIY tips include checking for loose or damaged wiring, ensuring proper connections, and reading the vehicle's manual for specific troubleshooting steps.

10. Is the U1842 code specific to Chevrolet vehicles?

While the U1842 code is specific to Chevrolet vehicles, similar communication issues may occur in other makes and models, each with their unique diagnostic codes.