Engine-Codes - Gmc - P0AA8 GMC

P0AA8 GMC - Hybrid/EV Battery Voltage Isolation Sensing Performance

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?
Table of contents

P0AA8 GMC Possible Causes

  • Faulty Starter/Generator Control Module
  • Starter/Generator Control Module harness is open or shorted
  • Starter/Generator Control Module circuit poor electrical connection

How is the P0AA8 GMC code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the P0AA8 GMC code

Labor: 1.0

The cost to diagnose the P0AA8 GMC code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
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Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0AA8 GMC Meaning

The vehicle is equipped with a high voltage isolation monitor feature. The purpose of the isolation monitor is to test the resistance between the high voltage positive and negative direct current (DC) bus and chassis ground. The isolation monitoring system measures the resistance between the high voltage system and chassis ground in the following way. The isolation monitoring system measures voltage potential difference between the positive battery mid pack voltage and chassis ground as well as the voltage difference between negative battery mid pack voltage and chassis ground. These voltage values are used by the starter/generator control module to calculate a resistance value between the high voltage bus and the chassis ground. If this resistance value is too low, a high voltage isolation fault has occurred.

More Information

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