AutoCodes – GMC – P1AC9 GMC

P1AC9 GMC 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 GMC 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.

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Code Popularity 1,140

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
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Code P1AC9 GMC Description

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

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

What does this mean?

What are the Possible Causes of the DTC P1AC9 GMC?

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 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 P1AC9 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 P1AC9 GMC Code

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

The common symptoms include illuminated warning lights on the dashboard, reduced vehicle performance, and potential issues with the hybrid battery system.

2. What are the possible causes of OBDII code P1AC9 (GMC) indicating HCM Service Calibration Fault?

Possible causes of this code include a fault in the Hybrid Control Module (HCM), software issues, wiring problems, or a malfunctioning hybrid system component.

3. How can I diagnose OBDII code P1AC9 (GMC) for HCM Service Calibration Fault?

Diagnosis typically involves using an OBDII scanner to retrieve the code, checking for other related codes, inspecting the hybrid system components for any visible damage, and performing a thorough system scan.

4. Can I continue driving my vehicle with OBDII code P1AC9 (GMC) showing HCM Service Calibration Fault?

It is not recommended to continue driving the vehicle with this code present, as it can lead to further damage to the hybrid system and potential safety hazards. It is advisable to have the issue diagnosed and repaired as soon as possible.

5. Are there any DIY repair tips for resolving OBDII code P1AC9 (GMC) related to HCM Service Calibration Fault?

DIY repair is not recommended for this code, as it involves complex components of the hybrid system. It is best to seek professional help from a certified technician with experience in hybrid vehicle repairs.

6. How much does it typically cost to repair OBDII code P1AC9 (GMC) indicating HCM Service Calibration Fault?

The cost of repair can vary depending on the exact cause of the fault, the extent of the damage, and the labor rates in your area. It is advisable to get a few quotes from different repair shops for an accurate estimate.

7. Can a software update fix OBDII code P1AC9 (GMC) related to HCM Service Calibration Fault?

In some cases, a software update provided by the manufacturer can resolve the calibration fault. It is recommended to check with the dealership or a qualified mechanic for the latest software updates for your vehicle.

8. What are the long-term effects of ignoring OBDII code P1AC9 (GMC) for HCM Service Calibration Fault?

Ignoring this code can lead to further damage to the hybrid system components, reduced fuel efficiency, and potential safety risks while driving. It is crucial to address the issue promptly to prevent costly repairs in the future.

9. Is OBDII code P1AC9 (GMC) indicating HCM Service Calibration Fault a common issue in GMC vehicles?

While not extremely common, this code can occur in GMC vehicles with hybrid systems, especially as the vehicle ages or if maintenance is neglected. Regular servicing and inspections can help prevent such issues.

10. How can I prevent OBDII code P1AC9 (GMC) related to HCM Service Calibration Fault from occurring in the future?

Regular maintenance of the hybrid system, including checking the wiring, monitoring the battery health, and following the manufacturer's recommended service schedule, can help prevent this code from appearing.