AutoCodes – Generic – P0AE3

P0AE3 Code - Hybrid Battery Precharge Contactor Circuit Stuck Open

Quick Answer

The SMRs (System Main Relays) connect and disconnect the high-voltage power supply circuit in accordance with requests from the HV control ECU. Common causes include Faulty System Main Relay, System Main Relay harness is open or shorted, System Main Relay 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: P0AE3 indicates Hybrid Battery Precharge Contactor Circuit Stuck Open.
Common causes: Common causes include Faulty System Main Relay, System Main Relay harness is open or shorted, System Main Relay 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 2,980

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 Oct 15, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0AE3 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 P0AE3 - Hybrid Battery Precharge Contactor Circuit Stuck Open - AutoCodes.com — P0AE3 Code - Hybrid Battery Precharge Contactor Circuit Stuck Open

What does this mean?

What are the Possible Causes of the DTC P0AE3?

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

How to Fix the DTC P0AE3?

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 P0AE3 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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Information for Specific Makes

P0AE3 Buick — Hybrid/EV Battery Precharge Contactor Circuit Stuck Open
P0AE3 Cadillac — Hybrid/EV Battery Precharge Contactor Circuit Stuck Open
P0AE3 Chevrolet — Hybrid/EV Battery Precharge Contactor Circuit Stuck Open
P0AE3 GMC — Hybrid/EV Battery Precharge Contactor Circuit Stuck Open
P0AE3 Lexus — Hybrid Battery Precharge Contactor Circuit Stuck Open
P0AE3 Nissan — Hybrid Battery Precharge Contactor Circuit Stuck Open
P0AE3 Saturn — Hybrid/EV Battery Precharge Contactor Circuit Stuck Open
P0AE3 Toyota — Hybrid Battery Precharge Contactor Circuit Stuck Open

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.