AutoCodes – Cadillac – P1A89 Cadillac

P1A89 Cadillac Code - 42 Volt System Voltage Low

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: P1A89 Cadillac indicates 42 Volt System Voltage Low.
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 939

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 P1A89 Cadillac 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 P1A89 Cadillac - 42 Volt System Voltage Low - AutoCodes.com — P1A89 Cadillac Code - 42 Volt System Voltage Low

What does this mean?

What are the Possible Causes of the DTC P1A89 Cadillac?

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 P1A89 Cadillac?

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 P1A89 Cadillac 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 P1A89 Cadillac Code

1. What does the OBDII code P1A89 Cadillac (42 Volt System Voltage Low) indicate?

The code P1A89 in a Cadillac indicates that the 42-volt system voltage is registering as low.

2. What are the common symptoms of OBDII code P1A89 in a Cadillac?

Common symptoms of this code may include dimming headlights, loss of power steering assist, and issues with the vehicle's electrical systems.

3. What are the possible causes of the OBDII code P1A89 in a Cadillac?

Possible causes of this code include a faulty 42-volt battery, a malfunctioning 42-volt generator, poor electrical connections, or a wiring issue.

4. How can I diagnose the OBDII code P1A89 in my Cadillac?

Diagnosing this code typically involves checking the 42-volt battery and generator, inspecting electrical connections, and testing the wiring for any faults.

5. Can I still drive my Cadillac with the OBDII code P1A89 present?

It is not recommended to drive your Cadillac with the P1A89 code present, as it can lead to further electrical issues and potential safety hazards.

6. How can I repair the OBDII code P1A89 in my Cadillac?

Repairing this code may involve replacing the 42-volt battery or generator, fixing any faulty wiring or connections, and clearing the code with a diagnostic tool.

7. Is it safe to reset the OBDII code P1A89 in my Cadillac without fixing the underlying issue?

Resetting the code without addressing the root cause may temporarily clear the warning light, but the issue will likely reoccur, potentially causing more severe problems.

8. How much does it cost to repair the OBDII code P1A89 in a Cadillac?

The cost of repairing this code can vary depending on the exact cause of the issue, but it may involve parts and labor costs for battery or generator replacement, wiring repairs, and diagnostics.

9. Can a DIY enthusiast fix the OBDII code P1A89 in a Cadillac?

While some basic troubleshooting steps can be taken by a DIY enthusiast, diagnosing and repairing issues related to the 42-volt system voltage may require specialized knowledge and tools best left to a professional.

10. How often does the OBDII code P1A89 occur in Cadillac vehicles?

The occurrence of the P1A89 code in Cadillac vehicles can vary, but it is typically not a common issue and may indicate a specific problem with the 42-volt system voltage.