AutoCodes – Cadillac – U1894 Cadillac

U1894 Cadillac Code - Hybrid Control Module Lost Communication With Starter/Generator 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 Starter/Generator Control Module (SGCM), Starter/Generator Control Module harness is open or shorted, Starter/Generator 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: U1894 Cadillac indicates Hybrid Control Module Lost Communication With Starter/Generator Control Module.
Common causes: Common causes include Faulty Starter/Generator Control Module (SGCM), Starter/Generator Control Module harness is open or shorted, Starter/Generator 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 479

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 U1894 Cadillac 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 U1894 Cadillac - Hybrid Control Module Lost Communication With Starter/Generator Control Module - AutoCodes.com — U1894 Cadillac Code - Hybrid Control Module Lost Communication With Starter/Generator Control Module

What does this mean?

What are the Possible Causes of the DTC U1894 Cadillac?

Faulty Starter/Generator Control Module (SGCM)
Starter/Generator Control Module harness is open or shorted
Starter/Generator Control Module circuit poor electrical connection
Faulty Hybrid Control Module (HCM)

How to Fix the DTC U1894 Cadillac?

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 U1894 Cadillac 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 U1894 Cadillac Code

1. What are the common symptoms of OBDII code U1894 in a Cadillac hybrid vehicle?

- Common symptoms include starting issues, stalling, loss of power, and the inability to switch between electric and gasoline modes.

2. What could cause the Hybrid Control Module to lose communication with the Starter/Generator Control Module in a Cadillac?

- Possible causes may include wiring issues, a faulty control module, software glitches, or a weak connection.

3. How can I diagnose the U1894 code in my Cadillac?

- Diagnosing the code typically involves using a professional OBDII scanner to retrieve the specific fault codes and inspecting the wiring and connections between the Hybrid Control Module and the Starter/Generator Control Module.

4. Is it safe to continue driving my Cadillac with the U1894 code present?

- It is not recommended to continue driving the vehicle with this code present, as it can lead to further electrical problems or potential safety hazards.

5. Can I repair the U1894 code in my Cadillac myself?

- While some basic troubleshooting steps can be taken, resolving this code often requires specialized diagnostic equipment and expertise. It is advisable to seek assistance from a qualified mechanic.

6. What are some tips for repairing the communication issue between the Hybrid Control Module and Starter/Generator Control Module?

- Check and secure all wiring connections, inspect for any visible damage, reset the control modules, and update the software to ensure compatibility and proper communication.

7. How much does it typically cost to repair the U1894 code in a Cadillac at a dealership or repair shop?

- Repair costs can vary depending on the exact cause of the issue, but it may range from a few hundred to over a thousand dollars, including parts and labor.

8. Are there any recalls or technical service bulletins related to the U1894 code in Cadillac hybrid vehicles?

- It is advisable to check with the Cadillac dealership or online resources for any relevant recalls or technical service bulletins related to this specific OBDII code.

9. Will resetting the fault codes using an OBDII scanner temporarily fix the U1894 code issue?

- Resetting the fault codes may temporarily clear the warning light, but if the underlying issue causing the code is not addressed, it is likely to reappear.

10. How can I prevent the U1894 code from occurring in my Cadillac in the future?

- Regular maintenance, proper handling of electrical components, and addressing any warning lights promptly can help prevent the recurrence of the U1894 code in your Cadillac.