AutoCodes – Buick – U1899 Buick

U1899 Buick Code - Starter/Generator Control Module Lost Communication With Powertrain 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 Powertrain Control Module (PCM), Powertrain Control Module harness is open or shorted, 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
U1899 Buick indicates Starter/Generator Control Module Lost Communication With Powertrain Control Module.
Common causes
Common causes include Faulty Powertrain Control Module (PCM), Powertrain Control Module harness is open or shorted, 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 465
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jun 08, 2020
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Code U1899 Buick 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 U1899 Buick - Starter/Generator Control Module Lost Communication With Powertrain Control Module - AutoCodes.com
U1899 Buick Code - Starter/Generator Control Module Lost Communication With Powertrain Control Module

What are the Possible Causes of the DTC U1899 Buick?

  • Faulty Powertrain Control Module (PCM)
  • Powertrain Control Module harness is open or shorted
  • Powertrain Control Module circuit poor electrical connection
  • Faulty Starter/Generator Control Module (SGCM)

How to Fix the DTC U1899 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 U1899 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.

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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 U1899 Buick Code

1. What does the OBDII code U1899 mean on a Buick?

The U1899 code indicates a loss of communication between the Starter/Generator Control Module (SGCM) and the Powertrain Control Module (PCM).

2. What are common symptoms of the U1899 code in a Buick?

Symptoms may include the engine failing to start, intermittent starting issues, a check engine light, or loss of hybrid system functionality if applicable.

3. What causes the U1899 code to appear?

The most common causes are wiring issues, loose or corroded connectors, a malfunctioning SGCM or PCM, or a software glitch in one of the modules.

4. Can a weak battery trigger the U1899 code?

Yes, a weak or failing battery can cause communication errors between modules, potentially triggering the U1899 code.

5. How do I diagnose the U1899 code on my Buick?

Start by checking the wiring and connectors between the SGCM and PCM for damage or corrosion. Use a scan tool to verify module communication and ensure the battery voltage is stable.

6. Can I drive my Buick with the U1899 code active?

Driving with this code is not recommended, as it may lead to engine starting problems or potential hybrid system malfunctions.

7. How can I fix the U1899 code on my Buick?

Repair or replace damaged wiring, clean corroded connectors, and update module software if needed. In some cases, replacing a faulty SGCM or PCM may be required.

8. Is the U1899 code specific to Buick vehicles?

No, the U1899 code can appear on other makes and models, but the affected modules and systems may vary.

9. Do I need to reprogram the modules after fixing the U1899 code?

In some cases, reprogramming or resetting the modules may be necessary to restore proper communication and functionality.

10. How much does it cost to repair the U1899 code on a Buick?

Repair costs vary depending on the issue but may range from $100 for simple wiring fixes to $1,000 or more if module replacement is required.

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