P0AA1 - Hybrid Battery Positive Contactor Circuit Stuck Closed

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

P0AA1 Possible Causes

  • Faulty System Main Relay
  • System Main Relay harness is open or shorted
  • System Main Relay circuit poor electrical connection
  • Faulty HV control ECU

How do I fix code P0AA1?

Check 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.
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Cost of diagnosing the P0AA1 code

Labor: 1.0

The cost of diagnosing the P0AA1 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

Possible Symptoms

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

P0AA1 Description

The SMRs (System Main Relays) connect and disconnect the high-voltage power supply circuit in accordance with requests from the HV control ECU. To ensure a reliable operation, they consists of a total of 3 relays (1 for the negative side and 2 for the positive side).
To connect, SMR1 and SMR3 turn ON initially. Then, SMR2 turns ON and SMR1 turns OFF. This process protects the circuit from the high-voltage surge current by allowing the limit current to flow via the resistor. To disconnect, SMR2 and SMR3 turn OFF in that order. The HV control ECU checks that the relays have turned OFF properly.
The HV control ECU monitors the proper operation of the SMRs (CON1, CON2 and CON3) to check for a malfunction.
OBDII Code P0aa1 - Hybrid Battery Positive Contactor Circuit Stuck Closed - AutoCodes.com

More Information

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Information for specific makes

  • P0AA1 BUICK Hybrid/EV Battery Positive Contactor Circuit Stuck Closed
  • P0AA1 CADILLAC Hybrid/EV Battery Positive Contactor Circuit Stuck Closed
  • P0AA1 CHEVROLET Hybrid/EV Battery Positive Contactor Circuit Stuck Closed
  • P0AA1 GMC Hybrid/EV Battery Positive Contactor Circuit Stuck Closed
  • P0AA1 LEXUS Hybrid Battery Positive Contactor Circuit Stuck Closed
  • P0AA1 NISSAN Hybrid Battery Positive Contactor Circuit Stuck Closed
  • P0AA1 SATURN Hybrid/EV Battery Positive Contactor Circuit Stuck Closed
  • P0AA1 TOYOTA Hybrid Battery Positive Contactor Circuit Stuck Closed

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