AutoCodes – GMC – P0A90 GMC

P0A90 GMC Code - Drive Motor Performance

Quick Answer

The generator control module also called the starter generator control module is comprised of the following three control modules; the hybrid powertrain control module, 14 volt power module and the drive motor control module. Common causes include Inspect the drive belt for cracks, wear and contamination, Faulty Starter Generator, Starter Generator harness is open or shorted. 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: P0A90 GMC indicates Drive Motor Performance.
Common causes: Common causes include Inspect the drive belt for cracks, wear and contamination, Faulty Starter Generator, Starter Generator harness is open or shorted.
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 777

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 Nov 20, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0A90 GMC Description

The generator control module also called the starter generator control module is comprised of the following three control modules; the hybrid powertrain control module, 14 volt power module and the drive motor control module. These three control modules are non serviceable and are part of the generator control module.
The eAssist hybrid system has a starter generator also called a drive motor. The starter generator is mounted to the front of the engine and is mechanically connected to the crankshaft pulley by a serpentine belt.
The hybrid powertrain control module receives an engine RPM signal over serial data and compares that value to the starter generator rpm received from the drive motor control module. The hybrid powertrain control module uses a ratio of these two speeds to determine if the drive belt is missing or slipping.

OBDII Code P0A90 GMC - Drive Motor Performance - AutoCodes.com — P0A90 GMC Code - Drive Motor Performance

What does this mean?

What are the Possible Causes of the DTC P0A90 GMC?

Inspect the drive belt for cracks, wear and contamination
Faulty Starter Generator
Starter Generator harness is open or shorted
Starter Generator circuit poor electrical connection

How to Fix the DTC P0A90 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 P0A90 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 P0A90 GMC Code

1. What does the OBDII code P0A90 mean on a GMC?

P0A90 indicates an issue with the drive motor's performance in a hybrid or electric vehicle. It typically points to a problem with the motor itself, the inverter, or related components.

2. What are the common symptoms of the P0A90 code?

Common symptoms include reduced power, the vehicle entering limp mode, warning lights on the dashboard, and unusual noises from the drive motor.

3. What causes the P0A90 code on a GMC?

This code can be caused by a faulty drive motor, inverter failure, wiring issues, or problems with the hybrid battery system.

4. Can I drive my GMC with a P0A90 code?

Driving with this code is not recommended, as it can lead to further damage to the hybrid or electric drivetrain components and reduced vehicle performance.

5. How is the P0A90 code diagnosed?

A technician will use a diagnostic scanner to retrieve the code, inspect the drive motor and inverter, check for wiring or connection issues, and test the hybrid battery system.

6. How can I fix the P0A90 code on my GMC?

Repairs may include replacing the drive motor, repairing or replacing the inverter, fixing damaged wiring, or addressing hybrid battery issues.

7. Is the P0A90 code covered under warranty?

Hybrid and electric drivetrain components often have a longer warranty. Check your GMC's warranty coverage, as the repair may be covered.

8. What tools are needed to troubleshoot a P0A90 code?

Diagnosing this code typically requires a professional-grade OBDII scanner, a multimeter for testing electrical circuits, and access to GMC's service manuals.

9. Can a weak hybrid battery cause the P0A90 code?

Yes, a weak or failing hybrid battery can impact the drive motor's performance and trigger the P0A90 code.

10. How much does it cost to repair the P0A90 code on a GMC?

Repair costs vary widely depending on the root cause. Fixing wiring issues might be inexpensive, but replacing a drive motor or inverter can cost several thousand dollars.