AutoCodes – Buick – U1842 Buick

U1842 Buick 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 Buick 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 764

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

What does this mean?

What are the Possible Causes of the DTC U1842 Buick?

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 Buick?

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 Buick 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 Buick code?

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Need Help with the Code?

Get the U1842 Buick 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 Buick Code

1. What are the common symptoms of OBDII code U1842 Buick (Lost Communication With ECM/PCM)?

- Common symptoms include engine stalling, rough idling, poor fuel economy, and difficulty starting the vehicle.

2. What are the possible causes of code U1842 in a Buick?

- The code U1842 (Lost Communication With ECM/PCM) in a Buick can be caused by issues such as loose or corroded wiring connections, a faulty ECM/PCM, or a communication network failure.

3. How can I diagnose the cause of OBDII code U1842 in my Buick?

- Diagnosing code U1842 involves checking the wiring connections, inspecting for any visible damage, testing the ECM/PCM, and using a scan tool to analyze communication on the network.

4. Can a DIY enthusiast repair OBDII code U1842 in a Buick?

- Repairing code U1842 may require advanced diagnostic tools and knowledge, so it is recommended to consult a professional mechanic for accurate diagnosis and repair.

5. Is it safe to drive my Buick with OBDII code U1842 (Lost Communication With ECM/PCM) present?

- It is not recommended to drive your Buick with code U1842 present, as it can lead to potential performance issues and safety concerns. Have the vehicle inspected and repaired as soon as possible.

6. How much does it typically cost to repair OBDII code U1842 in a Buick?

- The cost of repairing code U1842 can vary depending on the underlying cause. It is best to get a diagnostic assessment from a qualified mechanic to determine the exact repair cost.

7. Can a faulty battery or alternator cause OBDII code U1842 in a Buick?

- Yes, a faulty battery or alternator can potentially cause communication issues leading to code U1842. It is important to check the battery and charging system as part of the diagnostic process.

8. Are there any common mistakes to avoid when troubleshooting code U1842 in a Buick?

- Common mistakes to avoid include overlooking simple wiring issues, skipping proper diagnostic steps, and attempting repairs without the necessary tools and expertise.

9. Will resetting the OBDII code U1842 in my Buick make the issue go away?

- Resetting the code may temporarily clear the warning light, but it will not fix the underlying problem causing code U1842. Proper diagnosis and repair are necessary to resolve the issue.

10. How long does it typically take to repair OBDII code U1842 in a Buick?

- The repair time for code U1842 can vary depending on the cause and complexity of the issue. Some repairs may be completed within a few hours, while others may take longer for diagnosis and parts replacement.