AutoCodes – Lexus – P0A03 Lexus

P0A03 Lexus Code - Motor Electronics Coolant Temperature Sensor Circuit High

Quick Answer

The power management control Electronic Control Unit (ECU) detects HV coolant temperature using the coolant temperature sensor built into the inverter with converter assembly. Common causes include Faulty Inverter with converter assembly, Inverter with converter assembly harness is open or shorted, Inverter with converter assembly 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: P0A03 Lexus indicates Motor Electronics Coolant Temperature Sensor Circuit High.
Common causes: Common causes include Faulty Inverter with converter assembly, Inverter with converter assembly harness is open or shorted, Inverter with converter assembly 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 1,455

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 22, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0A03 Lexus Description

The power management control Electronic Control Unit (ECU) detects HV coolant temperature using the coolant temperature sensor built into the inverter with converter assembly. The power management control ECU uses signals from the coolant temperature sensor to check the effectiveness of the inverter cooling system. If necessary, the power management control ECU will limit inverter output to help prevent inverter overheating. The power management control ECU also detects malfunctions in the sensor based on the HV coolant temperature sensor values. The inverter with converter assembly detects malfunctions in the HV coolant temperature sensor and its wiring.

OBDII Code P0A03 Lexus - Motor Electronics Coolant Temperature Sensor Circuit High - AutoCodes.com — P0A03 Lexus Code - Motor Electronics Coolant Temperature Sensor Circuit High

What does this mean?

What are the Possible Causes of the DTC P0A03 Lexus?

Faulty Inverter with converter assembly
Inverter with converter assembly harness is open or shorted
Inverter with converter assembly circuit poor electrical connection

How to Fix the DTC P0A03 Lexus?

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 P0A03 Lexus 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.