AutoCodes – Buick – P1A9D Buick

P1A9D Buick Code - Starter/Generator Inverter Phase U Temperature Sensor Circuit High Voltage

Quick Answer

The Power Inverter Module (PIM) temperature 1 and 2 sensors are used for overheat protection. Common causes include Faulty Starter/Generator Control Module (SGCM), Starter/Generator Control Module (SGCM) harness is open or shorted, Starter/Generator Control Module (SGCM) 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: P1A9D Buick indicates Starter/Generator Inverter Phase U Temperature Sensor Circuit High Voltage.
Common causes: Common causes include Faulty Starter/Generator Control Module (SGCM), Starter/Generator Control Module (SGCM) harness is open or shorted, Starter/Generator Control Module (SGCM) 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 820

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 24, 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 P1A9D Buick Description

The Power Inverter Module (PIM) temperature 1 and 2 sensors are used for overheat protection. The thermistors are located on the control board, near the phase U or V power MOSFET. The Starter/Generator Control Module (SGCM) monitors the inverter temperature sensor for the following:
To detect if the inverter phase U or V temperature sensor is shorted low.
To detect if the inverter phase U or V temperature sensor is shorted high.

OBDII Code P1A9D Buick - Starter/Generator Inverter Phase U Temperature Sensor Circuit High Voltage - AutoCodes.com — P1A9D Buick Code - Starter/Generator Inverter Phase U Temperature Sensor Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1A9D Buick?

Faulty Starter/Generator Control Module (SGCM)
Starter/Generator Control Module (SGCM) harness is open or shorted
Starter/Generator Control Module (SGCM) circuit poor electrical connection

How to Fix the DTC P1A9D 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 P1A9D 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 P1A9D Buick code?

Need more information on how to fix the P1A9D Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1A9D 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 P1A9D Buick Code

1. What does the OBDII code P1A9D mean on a Buick?

The P1A9D code indicates a high voltage issue in the Starter/Generator Inverter Phase U Temperature Sensor Circuit, which monitors the temperature of the inverter's Phase U component.

2. What are the common symptoms of the P1A9D code on a Buick?

Symptoms may include an illuminated check engine light, reduced hybrid or electric performance, overheating of the inverter, or limited vehicle operation modes.

3. What causes the P1A9D code to appear?

Possible causes include a faulty temperature sensor, damaged wiring or connectors, malfunctioning starter/generator inverter, or issues with the vehicle's powertrain control module (PCM).

4. Can I drive my Buick with the P1A9D code present?

Itâ€™s not recommended to drive with this code because it may lead to overheating or damage to the electrical system. Have the issue diagnosed and repaired promptly.

5. How do you diagnose the P1A9D code on a Buick?

Diagnosis involves scanning the vehicle with an OBDII tool, inspecting the temperature sensor and its wiring, checking the inverter for faults, and testing the PCM for proper function.

6. How is the P1A9D code fixed on a Buick?

Repairs may include replacing the temperature sensor, repairing or replacing damaged wiring or connectors, or servicing/replacing the starter/generator inverter.

7. How much does it cost to repair the P1A9D code on a Buick?

Repair costs vary but may range from $100 to $500 depending on whether the issue is with the sensor, wiring, or inverter unit.

8. Can a bad PCM cause the P1A9D code?

Yes, a malfunctioning PCM can misinterpret sensor data or fail to regulate the inverter system properly, triggering the P1A9D code.

9. How do I prevent the P1A9D code from recurring?

Regular maintenance, inspecting electrical connections, and addressing inverter cooling system issues can help prevent this code from recurring.

10. Is the P1A9D code unique to Buick vehicles?

No, the code can appear on other vehicles with similar hybrid or electric systems, but its specifics and troubleshooting steps may vary by manufacturer.