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:

The DTC shown in the table below is output

OUTPUT DTC (HV)

DTC No.	Relevant Diagnosis
P0A1A (all details), P0A1B (all details), P0A1C (all details)	MG ECU circuit malfunction
P0A1D (all details)	HV ECU circuit malfunction
P0A3F (all details), P0A40 (all details), P0A41 (all details)	Motor resolver circuit malfunction
P0A45 (all details), P0A46 (all details), P0A47 (all details)	Rear motor resolver circuit malfunction
P0A4B (all details), P0A4C (all details), P0A4D (all details)	Generator resolver circuit malfunction
P0A51 (all details), P0A55 (all details)	MG ECU circuit malfunction
P0A60 (all details), P0A63 (all details)	Motor current sensor circuit
P0A69 (all details), P0A6C (all details)	Rear motor current sensor circuit
P0A72 (all details), P0A75 (all details)	Generator current sensor circuit
P0A78-510, 508, 586, 266, 272, 280, 304, 267, 278, 283, 285, 305, 523	Motor inverter function malfunction
P0A79-703, 701, 672, 690, 691, 697, 698	Rear motor inverter function malfunction
P0A7A-522, 520, 309, 321, 323, 342, 343	Generator inverter function malfunction
P0A94-585, 587, 561, 551, 588, 589, 545, 546, 552, 558, 559, 583, 584, 590	Boost converter circuit
P0AA6 (all details)	High-voltage system insulation malfunction
P3004-132	High-voltage system
P3232-749, P3233-750	HV gate shutdown wiring malfunction

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.
P0A78-306 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 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 1: 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
CHECK W/ CONVERTER INVERTER ASSEMBLY (MOTOR)
CAUTION: Be sure to wear insulated gloves.
1. Check that the service plug grip is removed.
2. Check that the bolts for the three-phase AC cable for Motor are tightened to the specified torque.
  Torque: 10 N*m (102 kgf*cm, 7 ft.*lbf)
NG: TIGHTEN THEM TO SPECIFIED TORQUE

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 of the HV Motor from the w/ converter inverter assembly.

Fig 3: Identifying Three-Phase AC Cable For Motor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: Measuring Resistance Of Three-Phase AC Cable For Motor (Shielded Wire Ground)
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 Rear 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 MEGOOHMMETER)

Tester Connection	Specified Condition
Three-phase AC Cable for Motor U terminal - Body ground and Shielded wire ground	10 MΩ 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: REPLACE W/ CONVERTER INVERTER ASSEMBLY