AutoCodes – GMC – U18BA GMC

U18BA GMC Code - Lost Communication With Power Steering Control Module On High Speed CAN Bus

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Power Steering Control Module, Power Steering Control Module harness is open or shorted, Power Steering 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: U18BA GMC indicates Lost Communication With Power Steering Control Module On High Speed CAN Bus.
Common causes: Common causes include Faulty Power Steering Control Module, Power Steering Control Module harness is open or shorted, Power Steering 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 515

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 09, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18BA GMC Description

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device. The Diagnostic Trouble Code (DTC) will set a supervised periodic message that includes the transmitter device availability that has not been received.

OBDII Code U18BA GMC - Lost Communication With Power Steering Control Module On High Speed CAN Bus - AutoCodes.com — U18BA GMC Code - Lost Communication With Power Steering Control Module On High Speed CAN Bus

What does this mean?

What are the Possible Causes of the DTC U18BA GMC?

Faulty Power Steering Control Module
Power Steering Control Module harness is open or shorted
Power Steering Control Module circuit poor electrical connection

How to Fix the DTC U18BA 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 U18BA 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 U18BA GMC Code

1. What does the OBDII code U18BA mean on a GMC vehicle?

U18BA indicates that the vehicle has lost communication with the Power Steering Control Module (PSCM) on the high-speed CAN (Controller Area Network) bus.

2. What are the common symptoms of the U18BA code?

Symptoms may include a loss of power steering assist, a warning light on the dashboard, stiffness in the steering wheel, and possible communication issues with other modules.

3. What causes the U18BA code to appear?

Common causes include a faulty Power Steering Control Module, damaged wiring or connectors in the CAN bus circuit, or a software issue within the module.

4. Can a low battery voltage cause the U18BA code?

Yes, low battery voltage or an unstable power supply can disrupt communication on the CAN bus and trigger the U18BA code.

5. How can I diagnose the U18BA code?

Start by checking for loose, corroded, or damaged wiring and connectors related to the Power Steering Control Module. Use a scan tool to verify communication with the module and inspect the CAN bus system for faults.

6. Can the U18BA code affect other vehicle systems?

Yes, since the CAN bus network connects multiple modules, a disruption in communication with the Power Steering Control Module could potentially affect other systems.

7. Is the U18BA code related to a mechanical power steering failure?

No, the U18BA code specifically refers to a communication issue, not a mechanical problem with the power steering system.

8. How is the U18BA code fixed?

Repairs may include replacing or reprogramming the Power Steering Control Module, repairing damaged wiring or connectors, or updating module software.

9. Can I drive with the U18BA code active?

Driving with the U18BA code may be possible, but it could result in limited or no power steering assist, making the vehicle harder to control, especially at low speeds.

10. Will clearing the U18BA code fix the problem?

Clearing the code may temporarily remove the warning, but the underlying issue must be resolved to prevent the code from returning.