AutoCodes – Generic – P1A8A

P1A8A Code - 42 Volt System Voltage High

Quick Answer

The Accessory Power Module (APM) supplies the energy that flows between the high voltage, 300 volt, direct current (DC) and intermediate voltage, 42 volt, DC to support the Electric Power Steering (EPS). Common causes include Faulty Accessory Power Module (APM), Accessory Power Module (APM) harness is open or shorted, Accessory Power Module (APM) 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: P1A8A indicates 42 Volt System Voltage High.
Common causes: Common causes include Faulty Accessory Power Module (APM), Accessory Power Module (APM) harness is open or shorted, Accessory Power Module (APM) 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 4,773

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 23, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1A8A Description

The Accessory Power Module (APM) supplies the energy that flows between the high voltage, 300 volt, direct current (DC) and intermediate voltage, 42 volt, DC to support the Electric Power Steering (EPS). The APM receives a 42 volt enable command from the Hybrid Powertrain Control Module (HPCM) over the high speed hybrid GMLAN communication circuit. 42 volt APM functions will run only when the 42 volt APM enable is active on the high speed hybrid GMLAN communication circuit.

OBDII Code P1A8A - 42 Volt System Voltage High - AutoCodes.com — P1A8A Code - 42 Volt System Voltage High

What does this mean?

What are the Possible Causes of the DTC P1A8A?

Faulty Accessory Power Module (APM)
Accessory Power Module (APM) harness is open or shorted
Accessory Power Module (APM) circuit poor electrical connection

How to Fix the DTC P1A8A?

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 P1A8A 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 P1A8A code?

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Information for Specific Makes

P1A8A Buick — 42 Volt System Voltage High
P1A8A Cadillac — 42 Volt System Voltage High
P1A8A Chevrolet — 42 Volt System Voltage High
P1A8A GMC — 42 Volt System Voltage High
P1A8A Saturn — 42 Volt System Voltage High

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 P1A8A Code

1. What are common symptoms of OBDII code P1A8A (42 Volt System Voltage High)?

Symptoms may include illuminated check engine light, reduced fuel efficiency, and issues with the vehicle's electrical system.

2. What can cause OBDII code P1A8A to trigger?

Possible causes include a faulty battery management system, overcharging of the 42-volt system, or a malfunctioning high-voltage battery.

3. How serious is OBDII code P1A8A (42 Volt System Voltage High)?

This code should be addressed promptly as it can lead to damage to the vehicle's electrical components and potentially pose a safety risk.

4. Can I continue driving with OBDII code P1A8A present?

It is not recommended to continue driving with this code active, as it can lead to further damage to the vehicle's electrical system.

5. How do I diagnose the root cause of OBDII code P1A8A?

Diagnosis typically involves using a diagnostic scanner to assess the 42-volt system's voltage levels and inspecting the battery management system for faults.

6. What are some possible repair tips for fixing OBDII code P1A8A?

Repair options may include replacing the high-voltage battery, addressing any issues with the battery management system, or resetting the system after correcting the voltage levels.

7. Can a DIY enthusiast fix OBDII code P1A8A at home?

While basic troubleshooting like checking the battery connections can be done at home, addressing the underlying causes of this code may require professional diagnostic equipment and expertise.

8. Are there any safety precautions to consider when dealing with OBDII code P1A8A?

Safety precautions include wearing appropriate protective gear when working around high-voltage components and following manufacturer guidelines for handling hybrid or electric vehicle systems.

9. How much does it cost to repair OBDII code P1A8A?

Costs can vary based on the extent of the issue, parts needed for replacement, and labor charges. It is advisable to obtain quotes from reputable automotive service centers.

10. Can OBDII code P1A8A be intermittent or temporary?

In some cases, this code may appear intermittently due to fluctuating voltage levels or temporary faults. However, it is essential to address the underlying issue to prevent reoccurrence.