P0A79-704

P310 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0A79-704: Drive Motor "B" Inverter Performance

DTC P0A79-704 - Drive Motor "B" Inverter Performance

DESCRIPTION

The inverter converts high-voltage direct current from the HV battery and alternating current for the Motor and Generator. The inverter contains a three-phase bridge circuit, which consists of six power transistors each for the Motor and the Generator, that converts direct current to three-phase alternating current. The MG ECU controls the actuation of the power transistors. The inverter transmits information that is necessary for effecting control, such as the amperage and voltage, to the MG ECU.

The MG ECU uses a voltage sensor, which is built into the inverter, to detect boosted high voltage for boost control.
The inverter voltage sensor outputs voltage that varies between 0 and 5 V in accordance with the changes in the high voltage. The higher the high-voltage, the higher the output voltage, and the lower the high-voltage, the lower the output voltage.
The MG ECU monitors the inverter voltage and detects a malfunction.

The MG ECU controls Motor torque according to driving conditions.

MONITOR DESCRIPTION

If the difference between the requested MGR torque and the actual MGR torque exceeds a predetermined value, the MG HVECU determines that there is a malfunction in the execution or monitoring of the MGR torque. Then, the HV control ECU illuminates the MIL and sets a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

INSPECTION PROCEDURE
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.

PROCEDURE

1. DTC OUTPUT (HV)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.
(d) Read output DTC. Hybrid Control System

Result:
The DTCs shown in the table below are output

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.
- P0A79-704 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 DTC CHART
NO -- Continue to next step.
2. CHECK REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY
CAUTION: Be sure to wear insulated gloves.

(a) Turn the ignition switch off and remove the service plug grip. Hybrid Control System

NOTE: Do not put the vehicle into the READY-on state with the service plug grip removed as this may cause a malfunction.
(b) Check that the bolts for the three-phase AC cable of the rear traction motor w/ transaxle assembly are tightened to the specified torque.
Torque: 15 Nm (153 kgf-cm, 11 ft-lbf)
NG -- TIGHTEN THEM TO SPECIFIED TORQUE
OK -- Continue to next step.
3. CHECK CONNECTION CONDITION OF MG ECU CONNECTOR (LOOSENESS AND POOR CONTACT)
CAUTION: Be sure to wear insulated gloves.

(a) Check that the service plug grip is removed.
(b) Remove the inverter cover. Components

NOTICE:
- 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.
(c) Check the connections of the MG ECU connectors.
Result:
Connectors are connected securely and there is no poor connection.
NG -- CONNECT SECURELY
OK -- Continue to next step.
4. CHECK W/ CONVERTER INVERTER ASSEMBLY (REAR MOTOR)
CAUTION: Be sure to wear insulated gloves.

(a) Check that the service plug grip is removed.
(b) Check that the bolts for the three-phase AC cable of the rear traction motor w/ transaxle assembly are tightened to the specified torque.
Torque: 10 Nm (102 kgf-cm, 7 ft-lbf)
NOTICE:
- Be sure to use a torque wrench to tighten the bolts.
- Make sure that the tightening torque is between 8.0 and 12 N*m {82 to 122 kgf*cm, 6 to 9 ft.*lbf}.

NG -- TIGHTEN THEM TO SPECIFIED TORQUE
OK -- Continue to next step.
5. INSPECT REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY
CAUTION: Be sure to wear insulated gloves.

(a) Check that the service plug grip is removed.
(b) Disconnect the three-phase AC cable for Rear Motor from the inverter.

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.
(d) To correct the resistance varying depending on the temperature, use the following formula to calculate the resistance at 68°F (20°C).
HINT:
- R20 = Rt / {1 + 0.00393 X (T - 20)}
- R20: Resistance at 68°F (20°C) (mOhms)
- Rt: Measured resistance (mOhms)
- T: Temperature when the resistance is measured (°C)
(e) Calculate the difference between the maximum and minimum resistance.
Standard resistance:
Difference is 5 mOhms or less
(f) Using a megohmmeter, measure the insulation resistance according to the value(s) in the table below.
NOTE: 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:

NG -- CHECK FRAME WIRE NO.3 (W/ CONVERTER INVERTER ASSEMBLY - REAR TRACTION MOTOR)
OK -- Continue to next step.
6. CHECK FRAME WIRE NO.3 (W/ CONVERTER INVERTER ASSEMBLY - REAR TRACTION MOTOR)
CAUTION: Be sure to wear insulated gloves.
(a) Check that the service plug grip is removed.

(b) Disconnect the three-phase AC cable for Rear Motor from the rear traction motor w/ transaxle assembly.

NG -- REPLACE FRAME WIRE NO.3
OK -- Continue to next step.
7. INSPECT EXTENSION WIRE ASSEMBLY
(a) Remove the rear traction motor w/ transaxle assembly. Components

(b) Remove the extension wire assembly from the rear traction motor w/ transaxle assembly. Components

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

(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:

NG -- REPLACE EXTENSION WIRE ASSEMBLY
OK -- REPLACE REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY
8. CHECK FRAME WIRE NO.3 (W/ CONVERTER INVERTER ASSEMBLY - REAR TRACTION MOTOR)
CAUTION: Be sure to wear insulated gloves.

(a) Check that the service plug grip is removed.
(b) Disconnect the three-phase AC cable from the rear motor.
NOTE: Wrap the terminals of disconnected cable with protective tape to prevent the terminals from contacting the vehicle body.
(c) Using a megohmmeter, measure the insulation resistance according to the value(s) in the table below.
NOTE: 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:

NG -- REPLACE FRAME WIRE NO.3
OK -- Continue to next step.
9. INSPECT EXTENSION WIRE ASSEMBLY
(a) Remove the rear traction motor w/ transaxle assembly. Components

(b) Remove the extension wire assembly from the rear traction motor w/ transaxle assembly. Components

(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:

NG -- REPLACE EXTENSION WIRE ASSEMBLY
OK -- REPLACE REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY