AutoCodes – GMC – P1AA8 GMC

P1AA8 GMC Code - Starter/Generator Field Control Performance

Quick Answer

The Starter/Generator Control Module (SGCM) monitors the Motor Generator Unit (MGU) field coil circuit to see if the field coil current is within tolerance. Common causes include Faulty Motor Generator Unit (MGU), Motor Generator Unit (MGU) harness is open or shorted, Motor Generator Unit (MGU) 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: P1AA8 GMC indicates Starter/Generator Field Control Performance.
Common causes: Common causes include Faulty Motor Generator Unit (MGU), Motor Generator Unit (MGU) harness is open or shorted, Motor Generator Unit (MGU) 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 874

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 Feb 26, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1AA8 GMC Description

The Starter/Generator Control Module (SGCM) monitors the Motor Generator Unit (MGU) field coil circuit to see if the field coil current is within tolerance.

OBDII Code P1AA8 GMC - Starter/Generator Field Control Performance - AutoCodes.com — P1AA8 GMC Code - Starter/Generator Field Control Performance

What does this mean?

What are the Possible Causes of the DTC P1AA8 GMC?

Faulty Motor Generator Unit (MGU)
Motor Generator Unit (MGU) harness is open or shorted
Motor Generator Unit (MGU) circuit poor electrical connection

How to Fix the DTC P1AA8 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 P1AA8 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.

Need more information about the P1AA8 GMC code?

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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 P1AA8 GMC Code

1. What are the common symptoms of OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- Common symptoms include difficulty starting the vehicle, reduced engine performance, and potential illumination of the check engine light.

2. What are the possible causes of OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- Possible causes may include a faulty starter/generator, issues with the field control module, wiring problems, or a malfunctioning control unit.

3. How can I diagnose OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- Diagnosing this code typically involves using a scan tool to retrieve the specific fault codes, checking the wiring and connections related to the starter/generator system, and testing the components for proper functionality.

4. Can I still drive my vehicle with OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- It is not recommended to drive the vehicle with this code active, as it can lead to potential issues with starting the engine and overall vehicle performance.

5. How can I repair OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- Repairing this code may involve replacing the faulty starter/generator, repairing or replacing damaged wiring, addressing issues with the field control module, or resetting the control unit as needed.

6. Will OBDII code P1AA8 GMC (Starter/Generator Field Control Performance) cause damage to other vehicle components?

- Ignoring this code can potentially lead to further damage to the starter/generator system and other related components, so it is important to address the issue promptly.

7. Are there any DIY tips for troubleshooting OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- DIY tips may include visually inspecting wiring for damage, checking connections for looseness or corrosion, and ensuring the battery is in good condition to support the starter/generator system.

8. Can a bad battery cause OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- Yes, a weak or faulty battery can sometimes trigger this code due to insufficient power supply to the starter/generator system.

9. How long does it typically take to repair OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- The repair time can vary depending on the exact cause of the issue, but it may take anywhere from a few hours to a day for diagnosis and repair.

10. Is it necessary to reset the OBDII system after repairing OBDII code P1AA8 GMC (Starter/Generator Field Control Performance)?

- Yes, it is recommended to reset the OBDII system after repairing the code to clear any stored fault codes and ensure proper functioning of the vehicle's systems.