AutoCodes – Buick – P1AC9 Buick

P1AC9 Buick Code - HCM Service Calibration Fault

Quick Answer

Hybrid Control Module (HCM) The internal fault detection is handled inside the control module. Common causes include Faulty Hybrid Control Module (HCM), Hybrid Control Module (HCM) harness is open or shorted, Hybrid Control Module (HCM) 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: P1AC9 Buick indicates HCM Service Calibration Fault.
Common causes: Common causes include Faulty Hybrid Control Module (HCM), Hybrid Control Module (HCM) harness is open or shorted, Hybrid Control Module (HCM) 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 982

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 Mar 01, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P1AC9 Buick Description

Hybrid Control Module (HCM) The internal fault detection is handled inside the control module. No external circuits are involved.

OBDII Code P1AC9 Buick - HCM Service Calibration Fault - AutoCodes.com — P1AC9 Buick Code - HCM Service Calibration Fault

What does this mean?

What are the Possible Causes of the DTC P1AC9 Buick?

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

How to Fix the DTC P1AC9 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 P1AC9 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.

Need more information about the P1AC9 Buick code?

Need more information on how to fix the P1AC9 Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1AC9 Buick code diagnosed by a professional: Find a repair shop in your area

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 P1AC9 Buick Code

1. What are common symptoms of the OBDII code P1AC9 Buick (HCM Service Calibration Fault)?

Common symptoms include illuminated warning lights on the dashboard, reduced fuel efficiency, and potential issues with the vehicle's hybrid battery system.

2. What does the OBDII code P1AC9 Buick (HCM Service Calibration Fault) indicate?

This code indicates a fault related to the Hybrid Control Module (HCM) service calibration within the vehicle's hybrid system.

3. What are some possible causes of the OBDII code P1AC9 Buick (HCM Service Calibration Fault)?

Possible causes include software glitches, issues with the hybrid control module, wiring problems, or a faulty hybrid battery.

4. How can I diagnose the OBDII code P1AC9 Buick (HCM Service Calibration Fault)?

Diagnosis typically involves using a professional OBDII scanner to retrieve the specific fault code and then performing further troubleshooting to pinpoint the exact cause.

5. Can I still drive my Buick with the OBDII code P1AC9 (HCM Service Calibration Fault)?

It is not recommended to continue driving the vehicle with this fault code present, as it can lead to potential issues with the hybrid system and affect the overall performance of the vehicle.

6. How can the OBDII code P1AC9 Buick (HCM Service Calibration Fault) be repaired?

Repairing this fault may involve recalibrating the hybrid control module, updating software, checking and repairing any wiring issues, or replacing faulty components in the hybrid system.

7. Is it necessary to take my Buick to a dealership for repairs related to the OBDII code P1AC9 (HCM Service Calibration Fault)?

While it is recommended to seek professional assistance for diagnosing and repairing this code, it is not always necessary to go to a dealership. Qualified auto repair shops with experience in hybrid systems can also address this issue.

8. What are the potential risks of ignoring the OBDII code P1AC9 Buick (HCM Service Calibration Fault)?

Ignoring this fault code can lead to further damage to the hybrid system, reduced fuel efficiency, and potential safety hazards while driving.

9. How long does it typically take to repair the OBDII code P1AC9 Buick (HCM Service Calibration Fault)?

The repair time can vary depending on the exact cause of the fault. It is best to consult with a professional technician for an accurate estimate of the repair duration.

10. Can I prevent the OBDII code P1AC9 Buick (HCM Service Calibration Fault) from occurring in the future?

Regular maintenance, timely software updates, and addressing any issues related to the hybrid system promptly can help prevent this fault code from occurring in the future.