ELECTROMAGNETIC SOUND HEARD

Malfunction symptom	Electromagnetic sound heard
Description	• While the vehicle is driven, sometimes the electromagnetic sound from the electric motor and inverter is louder than normal.
Possible cause	Vehicle is driven under heavy load: • Electromagnetic sound from electric motor and inverter becomes louder when accelerating from standstill (large output torque) on steep slope (Normal operation) ― To prevent a malfunction occurring when the power transistor in the inverter becomes hot due to driving under heavy load, control is performed by lowering the power transistor switching frequency.
System wiring diagram	• Not applicable
Connector diagram	• Not applicable

Malfunction symptom

Electromagnetic sound heard

Description

• While the vehicle is driven, sometimes the electromagnetic sound from the electric motor and inverter is louder than normal.

Possible cause

Vehicle is driven under heavy load:

• Electromagnetic sound from electric motor and inverter becomes louder when accelerating from standstill (large output torque) on steep slope (Normal operation)

― To prevent a malfunction occurring when the power transistor in the inverter becomes hot due to driving under heavy load, control is performed by lowering the power transistor switching frequency.

System wiring diagram

• Not applicable

Connector diagram

• Not applicable

Step	Inspection	Results	Action
1	DETERMINE IF SYMPTOM IS CAUSED BY POOR ACCELERATION OR INSUFFICIENT POWER • Cool down the vehicle to decrease the temperature of the electric motor and inverter. Warning • Observe legal speed limits when driving the vehicle and perform the procedure in a location where safety can be assured. • Drive the vehicle. Note • If the vehicle is repeatedly accelerated from a standstill (large output torque) on a steep slope, the output decreases to protect the parts. Identify the symptoms within a short period of time. • Does a poor acceleration or insufficient power symptom occur?	Yes	Perform troubleshooting according to [VEHICLE CANNOT ACCELERATE FROM STANDSTILL, POOR ACCELERATION, INSUFFICIENT POWER]. (See VEHICLE CANNOT ACCELERATE FROM STANDSTILL, POOR ACCELERATION, INSUFFICIENT POWER.)
No	Go to the next step.
2	ELECTRIC MOTOR TORQUE RESTRICTION OF DRIVE MOTOR CONTROL MODULE • Connect the M-MDS to the DLC-2. • Switch the main power ON (READY off). • Activate the M-MDS and perform the following procedure. 1. Press [Start] to start the vehicle identification. 2. Press the [Toolbox] tab. 3. Press the [Diagnosis] icon. 4. Press [Operational records]. 5. Press [EV]. 6. Press [Run] for [Reading records of Electric Motor torque restriction]. • Display the electric motor torque restriction records according to the directions on the M-MDS screen. • Do the electric motor torque restriction records display and the customer-stated symptoms match the driving condition that occurred?	Yes	Explain to the customer that this condition occurs to protect parts when the electric motor and inverter temperatures become high when the vehicle accelerates from a standstill on a steep slope or the vehicle is driven under a heavy load with sudden acceleration.
No	Compare the noise level of the electromagnetic sound with another vehicle of the same model. Electromagnetic sound is the same level or less than another vehicle of the same model: • Explain to the customer that the electromagnetic sound is a unique sound made by electric vehicles and that this does not indicate a problem. Electromagnetic sound is louder than another vehicle of the same model: • Explain to the customer that this condition occurs to protect parts when the electric motor and inverter temperatures become high when the vehicle accelerates from a standstill on a steep slope or the vehicle is driven under a heavy load with sudden acceleration.

Step

Inspection

Results

Action

DETERMINE IF SYMPTOM IS CAUSED BY POOR ACCELERATION OR INSUFFICIENT POWER

• Cool down the vehicle to decrease the temperature of the electric motor and inverter.

Warning

• Observe legal speed limits when driving the vehicle and perform the procedure in a location where safety can be assured.

• Drive the vehicle.

Note

• If the vehicle is repeatedly accelerated from a standstill (large output torque) on a steep slope, the output decreases to protect the parts. Identify the symptoms within a short period of time.

• Does a poor acceleration or insufficient power symptom occur?

Yes

Perform troubleshooting according to [VEHICLE CANNOT ACCELERATE FROM STANDSTILL, POOR ACCELERATION, INSUFFICIENT POWER].

(See VEHICLE CANNOT ACCELERATE FROM STANDSTILL, POOR ACCELERATION, INSUFFICIENT POWER.)

Go to the next step.

ELECTRIC MOTOR TORQUE RESTRICTION OF DRIVE MOTOR CONTROL MODULE

• Connect the M-MDS to the DLC-2.

• Switch the main power ON (READY off).

• Activate the M-MDS and perform the following procedure.

1. Press [Start] to start the vehicle identification.

2. Press the [Toolbox] tab.

3. Press the [Diagnosis] icon.

4. Press [Operational records].

5. Press [EV].

6. Press [Run] for [Reading records of Electric Motor torque restriction].

• Display the electric motor torque restriction records according to the directions on the M-MDS screen.

• Do the electric motor torque restriction records display and the customer-stated symptoms match the driving condition that occurred?

Yes

Explain to the customer that this condition occurs to protect parts when the electric motor and inverter temperatures become high when the vehicle accelerates from a standstill on a steep slope or the vehicle is driven under a heavy load with sudden acceleration.

Compare the noise level of the electromagnetic sound with another vehicle of the same model.

Electromagnetic sound is the same level or less than another vehicle of the same model:

• Explain to the customer that the electromagnetic sound is a unique sound made by electric vehicles and that this does not indicate a problem.

Electromagnetic sound is louder than another vehicle of the same model:

• Explain to the customer that this condition occurs to protect parts when the electric motor and inverter temperatures become high when the vehicle accelerates from a standstill on a steep slope or the vehicle is driven under a heavy load with sudden acceleration.