Inspection Procedure

WARNING: This page is about a different car, the 2006 Lexus RX 400h. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION:

Before inspecting the high-voltage system, take safety precautions to prevent electrical shocks, such as wearing insulated gloves and removing the service plug grip. After removing the service plug grip, put it in your pocket to prevent other technicians from reconnecting it while you are working on the high-voltage system.
After disconnecting the service plug grip, wait for at least 5 minutes before touching any of the high-voltage connectors or terminals.

HINT:

At least 5 minutes is required to discharge the high-voltage capacitor inside the w/ converter inverter assembly.

READ OUTPUT DTC (HV)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to the ON position.
Select the following menu items: DIAGNOSIS / OBD/ MOBD / HV ECU / DTC INFO / CURRENT CODES.

Read output DTCs. (See DTC CHECK / CLEAR )

Result:

Any of the following DTCs are output

OUTPUT DTC (HV)

DTC No.	Relevant Diagnosis
P0A1D	HV ECU circuit malfunction
P0A2B, P0A2C, P0A2D	Motor temperature sensor circuit
P0A37, P0A38, P0A39	Generator temperature sensor circuit
P0A3F, P0A40, P0A41	Motor resolver circuit
P0A4B, P0A4C, P0A4D	Generator resolver circuit
P0A60, P0A63	Motor current sensor circuit
P0A72, P0A75	Generator current sensor circuit
P0A78 (Except for 284, 806, 807, and 808)	Motor inverter function malfunction
P0A7A	Generator inverter function malfunction
P0A90	Motor function malfunction
P0A92	Generator function malfunction
P0A93	Inverter cooling system
P0A94	Boost converter circuit
P0AA1, P0AA2, P0AA4, P0AA5	System main relay circuit
P3000, P3003, P0AA6, P3110	High-voltage system
P0AEE, P0AEF, P0AF0	Motor inverter temperature sensor circuit
P3221	Generator inverter temperature sensor circuit
P3226	Boost converter temperature sensor circuit
P0A05	Water pump w/ Motor malfunction
P0A79	Rear Motor inverter function malfunction
P0AF3, P0AF4, P0AF5	Rear Motor temperature sensor malfunction
P0A45, P0A46, P0A47	Rear Motor resolver malfunction
P0A69, P0A6C, P0A55	Rear Motor current sensor circuit
P0A1A, P0A1B, P0A1C	MG ECU malfunction

NOTE: If P0A78-284 is output, repair the malfunctioning area indicated by the DTC, or replace the w/converter inverter assembly after repairing the malfunctioning area.

HINT:

Turning the ignition switch to the ON position with the service plug grip and inverter cover removed causes interlock switch system DTC P0A0D-350 to be output.
P0A78-284 may be output due to a malfunction which causes the DTCs in the table above to be output. In this case, first troubleshoot the output DTCs in the table above. Then, perform a reproduction test to check that no DTCs are output.

YES: GO TO DIAGNOSTIC TROUBLE CODE CHART

NO: GO TO NEXT STEP

CHECK QUANTITY OF HV COOLANT
1. Check the inverter coolant level.
  OK:
  
  There is sufficient amount of coolant for the inverter.
NG: CHECK FOR COOLANT LEAKS AND ADD COOLANT

OK: GO TO NEXT STEP
CHECK COOLANT HOSE
1. Check that the hoses of the cooling system are not bent or clogged.
  OK:
  
  The hoses of the cooling system are not bent or clogged.
Fig 1: Checking Coolant Hose
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: CORRECT TO NORMAL CONDITION

OK: GO TO NEXT STEP
CHECK CONNECTION CONDITION OF WATER PUMP CONNECTOR (LOOSENESS AND POOR CONTACT)
1. Check the connection of the water pump w/ motor & bracket assembly connector.
  OK:
  
  Connector is connected securely and there is no poor connection.
Fig 2: Checking Connection Condition Of Water Pump Connector (Looseness And Poor Contact)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: CONNECT SECURELY

OK: GO TO NEXT STEP
PERFORM ACTIVE TEST BY INTELLIGENT TESTER (WATER PUMP)
1. Connect the intelligent tester to the DLC3.
2. Turn the ignition switch to the ON position.
3. Select the following menu items: DIAGNOSIS / OBD/ MOBD / HV ECU / ACTIVE TEST / WATER PUMP.
4. During the WATER PUMP active test, check operation of the water pump.
  OK:
  
  There are ripples in the reservoir tank coolant.
  
  HINT:
  
  The water pump is also activated in the READY-on state.
NG: REPLACE WATER PUMP W/ MOTOR & BRACKET ASSEMBLY CIRCUIT

OK: GO TO NEXT STEP
PERFORM ACTIVE TEST BY INTELLIGENT TESTER (COOLING FAN)
1. Connect the intelligent tester to the DLC3.
2. Turn the ignition switch to the ON position.
3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / ENGINE / ACTIVE TEST / COOLING FAN.
4. Perform the electric cooling fan active test.
  OK:
  
  The electric cooling fan rotates.
NG: CHECK COOLING FAN CIRCUIT

OK: GO TO NEXT STEP
CHECK CONNECTION CONDITION OF HYBRID VEHICLE CONTROL ECU CONNECTOR (LOOSENESS AND POOR CONTACT)
1. Check the connections of all HV control ECU connectors.
  OK:
  
  Connectors are connected securely and there is no poor connection.
NG: CONNECT SECURELY

OK: GO TO NEXT STEP
CHECK CONNECTION CONDITION OF MG ECU CONNECTOR (LOOSENESS AND POOR CONTACT)
CAUTION: Be sure to wear insulated gloves.
1. Turn the ignition switch off and remove the service plug grip. (See PRECAUTION )
  NOTE: Do not put the vehicle into the READY-on state with the service plug grip removed as this may cause a malfunction.
2. Remove the inverter cover. (See INVERTER WITH CONVERTER )
  NOTE:
  - Wrap the interlock round terminal for the inverter cover with vinyl tape to prevent it from shorting to ground.
  - Prevent water in the reservoir tank from entering the inverter.
  - Removing the inverter cover causes the MG ECU board to be exposed. Therefore, temporarily install the inverter cover for each area to be inspected.
3. Check the connections of the MG ECU connectors.
  OK:
  
  Connectors are connected securely and there is no poor connection.
  
  Fig 4: Checking Connection Condition Of MG ECU Connector (Looseness And Poor Contact)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: CONNECT SECURELY

OK: GO TO NEXT STEP

INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR)

CAUTION: Be sure to wear insulated gloves.

Check that the service plug grip is removed.
Disconnect the three-phase AC cable for Motor from the w/ converter inverter assembly.

Fig 5: Identifying Three-Phase AC Cable For Motor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 6: Measuring Resistance Of Three-Phase AC Cable For Motor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard Resistance

HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR) (USING MILLIOHMMETER)

Tester Connection	Specified Condition
U - V	48 to 59 mΩ (20°C)
V - W	48 to 59 mΩ (20°C)
W - U	48 to 59 mΩ (20°C)

NOTE: If the Motor temperature is too high, the resistance changes greatly. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

To correct the resistance varying depending on the temperature, use the following formula to calculate the resistance at 20°C.
HINT:
- R20 = Rt / {1 + 0.00393 X (T - 20)}
- R20: Resistance at 20 °C (mΩ)
- Rt: Measured resistance (mΩ)
- T: Temperature when the resistance is measured (°C)
Calculate the difference between the maximum and minimum resistance.
Standard Resistance:

Difference is 5 mΩ or less

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

Standard Resistance

HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR) (USING MEGOHMMETER)

Tester Connection	Specified Condition
Three-phase AC Cable for Motor U terminal - Body ground and shielded wire ground	10MΩ or higher
Three-phase AC Cable for Motor V terminal - Body ground and shielded wire ground	10 MΩ or higher
Three-phase AC Cable for Motor W terminal - Body ground and shielded wire ground	10 MΩ or higher

NG: REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

OK: GO TO NEXT STEP

CHECK HARNESS AND CONNECTOR (MG ECU - MOTOR RESOLVER)

CAUTION: Be sure to wear insulated gloves.

Check that the service plug grip is removed.
Disconnect the I22 connector from the MG ECU.

Measure the voltage according to the value(s) in the table below when the ignition switch is in the ON position.

Fig 7: Checking Harness And Connector (MG ECU - Motor Resolver)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard Voltage

MG ECU - MOTOR RESOLVER (VOLTAGE)

Tester Connection	Specified Condition
MRF (I22-13) - Body ground	Below 1 V
MRFG (I22-23) - Body ground	Below 1 V
MSN (I22-21) - Body ground	Below 1 V
MSNG (I22-20) - Body ground	Below 1V
MCS (I22-19) - Body ground	Below 1 V
MCSG (I22-18) - Body ground	Below 1 V

NOTE: Turning the ignition switch to the ON position with the MG ECU connectors disconnected causes other DTCs to be stored. Clear the DTCs after performing the inspection.

Turn the ignition switch off.

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

Standard Resistance

MG ECU - MOTOR RESOLVER (1 OF 2)

Tester Connection	Specified Condition
MRF (I22-13) - MRFG (I22-23)	7.65 to 10.2 Ω
MSN (I22-21) - MSNG (I22-20)	12.6 to 16.8 Ω
MCS (I22-19) - MCSG (I22-18)	12.6 to 16.8 Ω

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

Standard Resistance

MG ECU - MOTOR RESOLVER (2 OF 2)

Tester Connection	Specified Condition
MRF (I22-13) or MRFG (I22-23) - Body ground	10 MΩ or higher
MSN (I22-21) or MSNG (I22-20) - Body ground	10 MΩ or higher
MCS (I22-19) or MCSG (I22-18) - Body ground	10 MΩ or higher

OK: REPLACE W/ CONVERTER INVERTER ASSEMBLY

NG: GO TO NEXT STEP

CHECK CONNECTION CONDITION OF MOTOR RESOLVER CONNECTOR (LOOSENESS AND POOR CONTACT)
1. Check the connection of the motor resolver connector.
  OK:
  
  Connector is connected securely and there is no poor connection.
Fig 8: Checking Connection Condition Of Motor Resolver Connector (Looseness And Poor Contact)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: CONNECT SECURELY

OK: GO TO NEXT STEP

INSPECT MOTOR RESOLVER

Disconnect the M14 motor resolver connector.

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

Standard Resistance

MOTOR RESOLVER (1 OF 2)

Tester Connection	Specified Condition
MRF (M14-1) - MRFG (M14-4)	7.65 to 10.2 Ω
MSN (M14-2) - MSNG (M14-5)	12.6 to 16.8 Ω
MCS (M14-3) - MCSG (M14-6)	12.6 to 16.8 Ω

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

Standard Resistance

MOTOR RESOLVER (2 OF 2)

Tester Connection	Specified Condition
MRF (M14-1) - MSN (M14-2)	10 MΩ or higher
MRF (M14-1) - MCS (M14-3)	10 MΩ or higher
MSN (M14-2) - MCS (M14-3)	10 MΩ or higher
MRFG (M14-4) - MSNG (M14-5)	10 MΩ or higher
MRFG (M14-4) - MCSG (M14-6)	10 MΩ or higher
MSNG (M14-5) - MCSG (M14-6)	10 MΩ or higher
Each terminal listed above - Transaxle housing	10 MΩ or higher

Fig 9: Inspecting Motor Resolver

NG: REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

OK: REPAIR OR REPLACE HARNESS OR CONNECTOR