Lexus ES: Motor High-voltage Circuit

Lexus ES (XZ10) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Control System (for Nickel Metal Hydride Battery) / Motor High-voltage Circuit

DESCRIPTION

The cause of the malfunction may be the high-voltage circuit of the motor.

Check the motor internal resistance and the connection condition of the high-voltage line between the inverter and motor to check whether there is an open or short circuit.

Related Parts Check

Area	Inspection
Motor cable connection check	Check for open or short circuit in the connection condition of the cable from the inverter to the motor.
Motor and motor cable	Check the motor (including cable) internal resistance and insulation resistance with body ground to check for an open or short circuit.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

This diagnostic procedure is referenced to in the diagnostic procedure of several DTCs.

If the result of this diagnostic procedure is normal, proceed as directed in the procedure for the DTC.

CAUTION:

Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.
- Inspecting the high-voltage system
- Disconnecting the low voltage connector of the inverter with converter assembly
- Disconnecting the low voltage connector of the HV battery
To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.
After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.

*a

Without waiting for 10 minutes

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HINT:

Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

NOTICE:

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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PROCEDURE

1.	CHECK INVERTER WITH CONVERTER ASSEMBLY (MOTOR CABLE CONNECTION CONDITION)

CAUTION:

Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:

After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Remove the inverter cover from the inverter with converter assembly.

(c) Check that the bolts for the motor cable are tightened to the specified torque, the motor cable is connected securely, and there are no contact problems.

Specified Condition:

T = 8.0 N*m (82 kgf*cm, 71 in.*lbf)

(d) Disconnect the motor cable from the inverter with converter assembly.

(e) Check for arc marks at the terminals for the motor cable.

Result		Proceed to
The terminals are connected securely and there are no contact problems.	There are no arc marks.	A
The terminals are not connected securely and there is a contact problem.	There are arc marks.	B
The terminals are not connected securely and there is a contact problem.	There are no arc marks.	C
The terminals are connected securely and there are no contact problems.	There are arc marks.	B

(f) Reconnect the motor cable.

(g) Reinstall the inverter cover.

REPLACE MALFUNCTIONING PARTS

CONNECT SECURELY

2.	CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR (MG2))

CAUTION:

Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:

After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Remove the inverter cover from the inverter with converter assembly.

(d) Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

HINT:

If the motor (MG2) temperature is high, the resistance will vary greatly from the specification. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

Standard Resistance:

Tester Connection	Condition	Specified Condition
Y2-1 (W) - Y2-2 (U)	Power switch off	62.1 to 68.8 mΩ
Y2-2 (U) - Y2-3 (V)	Power switch off	62.1 to 68.8 mΩ
Y2-3 (V) - Y2-1 (W)	Power switch off	62.3 to 69.0 mΩ

HINT:

To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68°F).

R20 = Rt / {1 + 0.00393 X (T - 20)}

The calculation is based on the following:

R20: Resistance at 20°C (68°F) (mΩ)

Rt: Measured resistance (mΩ)

T: Temperature when the resistance is measured (°C (°F).)

Shield Ground

Motor Cable

(Inverter with Converter Assembly Side)

(e) Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

NOTICE:

Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

Standard Resistance:

Tester Connection	Condition	Specified Condition
Y2-1 (W) - Body ground and shield ground	Power switch off	100 MΩ or higher
Y2-2 (U) - Body ground and shield ground	Power switch off	100 MΩ or higher
Y2-3 (V) - Body ground and shield ground	Power switch off	100 MΩ or higher

(f) Reconnect the motor cable.

(g) Reinstall the inverter cover.

MOTOR HIGH-VOLTAGE CIRCUIT NORMAL (PERFORM NEXT STEP FOR REFERENCED DTC)

3.	CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR CABLE CONNECTION CONDITION)

CAUTION:

Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:

After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Remove the inverter with converter assembly.

(c) Check that the bolts for the motor cable are tightened to the specified torque, the motor cable is connected securely, and there are no contact problems.

Specified Condition:

T=10 N*m (102 kgf*cm, 7 ft.*lbf)

(d) Disconnect the motor cable from the hybrid vehicle transaxle assembly.

(e) Check for arc marks at the terminals for the generator cable.

Result		Proceed to
The terminals are connected securely and there are no contact problems.	There are no arc marks.	A
The terminals are not connected securely and there is a contact problem.	There are arc marks.	B
The terminals are not connected securely and there is a contact problem.	There are no arc marks.	C
The terminals are connected securely and there are no contact problems.	There are arc marks.	B

(f) Reconnect the motor cable.

(g) Reinstall the inverter with converter assembly.

REPLACE MALFUNCTIONING PARTS

CONNECT SECURELY

4.	CHECK MOTOR CABLE (FOR MG2)

CAUTION:

Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:

After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Remove the inverter with converter assembly.

(d) Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

NOTICE:

Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

*1	Shielded Ground	-	-
*a	Motor Cable	-	-

Standard Resistance:

Tester Connection	Condition	Specified Condition
Y2-1 (W) or Y1-1 (W) - Shield ground	Power switch off	100 MΩ or higher
Y2-2 (U) or Y1-2 (U) - Shield ground	Power switch off	100 MΩ or higher
Y2-3 (V) or Y1-3 (V) - Shield ground	Power switch off	100 MΩ or higher

NOTICE:

Wrap the terminal of the motor cable with insulating tape to prevent them from coming into contact with body ground.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
Y2-1 (W) - Y1-1 (W)	Power switch off	Below 1 Ω
Y2-2 (U) - Y1-2 (U)	Power switch off	Below 1 Ω
Y2-3 (V) - Y1-3 (V)	Power switch off	Below 1 Ω
Y2-1 (W) - Y1-2 (U)	Power switch off	100 MΩ or higher
Y2-2 (U) - Y1-3 (V)	Power switch off	100 MΩ or higher
Y2-3 (V) - Y1-1 (W)	Power switch off	100 MΩ or higher

(f) Reinstall the motor cable.

(g) Reinstall the inverter with converter assembly.

REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

REPLACE MOTOR CABLE

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