P0A78-128

L110F HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0A78-128: Drive Motor "A" Inverter Performance

DTC P0A78-128 - Drive Motor "A" Inverter Performance

DESCRIPTION

For a description of the inverter, P0A78-266.
If the motor inverter overheats, has a circuit malfunction, or has an internal short, the inverter transmits this information to the MG ECU via the motor inverter fail signal line.
If an abnormal amount of current flows through the motor inverter, the MG ECU detects it and sends a signal to inform the hybrid vehicle control ECU of the malfunction.
HINT: The term "drive motor A" indicates MG2.

MONITOR DESCRIPTION

The MG ECU monitors the motor inverter electric current. If the current exceeds the threshold for a specified period of time, the hybrid vehicle control ECU will illuminate the MIL and set a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

INSPECTION PROCEDURE
CAUTION:
- Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
- After disconnecting the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting, check the voltage at the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.
HINT: Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

PROCEDURE

1. CHECK DTC OUTPUT (HV)
(a) Connect the intelligent tester or Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Select the following menu items:
(1) Intelligent tester - Select: DIAGNOSIS / OBD/MOBD / HV ECU / DTC INFO / CURRENT CODES.
(2) Techstream - Select: Powertrain / Hybrid Control / Trouble Codes.
(d) Check if DTCs are output.
Result:

B -- GO TO DTC OUTPUT
A -- Continue to next step.
2. CHECK DTC OUTPUT (HV)
(a) Connect the intelligent tester or Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Select the following menu items:
(1) Intelligent tester - Select: DIAGNOSIS / OBD/MOBD / HV ECU / DTC INFO / CURRENT CODES.
(2) Techstream - Select: Powertrain / Hybrid Control / Trouble Codes.
(d) Check if DTCs are output.
Result:

HINT:
- *1: If any INF codes are output for this DTC, refer to the corresponding diagnostic flowchart.
- P0A78-128 may be set due to a malfunction which also causes DTCs in the preceding table to be set. In this case, first troubleshoot the output DTCs in the preceding table. Then, perform a test to attempt to reproduce the problems, and check that no DTCs are output.

B -- GO TO DTC CHART
A -- Continue to next step.
3. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR)
NOTE: Before disconnecting the connector, confirm that it is properly connected by checking that the locking claws are engaged and that the connector does not pull out.

(a) Check the connection of the low voltage connector of the inverter with converter assembly.
OK:
The connector is connected securely and there are no contact problems.
HINT: When connecting the connector, insert it with the locking lever in the raised position. Rotate the lever downward and make sure that the connector is pulled into its socket. When the locking lever is in its fully closed position, a click will be heard as its locking claws engage. After the click is heard, pull up on the connector to confirm that it is properly connected.

NG -- CONNECT SECURELY
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - GENERATOR RESOLVER)
CAUTION: Be sure to wear insulated gloves.
(a) Turn the power switch off.
(b) Remove the service plug grip. L110F Hybrid Vehicle Control System

NOTE: 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.

(e) Measure the voltage according to the value(s) in the table below.
Standard voltage :

NOTE: Turning the power switch on (IG) with the low voltage connector of the inverter with converter assembly disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK GENERATOR RESOLVER

(a) Turn the power switch off.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):

Standard resistance (Check for short):

NG -- CHECK CONNECTOR CONNECTION CONDITION (GENERATOR RESOLVER CONNECTOR)
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - MOTOR RESOLVER)
(a) Turn the power switch on (IG).

(b) Disconnect the low voltage connector from the inverter with converter assembly.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage :

(a) Turn the power switch off.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):

Standard resistance (Check for short):

NG -- CHECK CONNECTOR CONNECTION CONDITION (MOTOR RESOLVER CONNECTOR)
OK -- Continue to next step.
8. CHECK INVERTER WITH CONVERTER ASSEMBLY (GENERATOR CABLE CONNECTION CONDITION)
CAUTION: Be sure to wear insulated gloves.
(a) Check that the service plug grip is not installed.

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

(c) Check that the bolts for the generator cable are tightened to the specified torque, the generator cable is connected securely, and there are no contact problems.
Specified Condition:
T=8.0 N*m {82 kgf*cm, 71 in.*lbf}
NOTE: Make sure that the tightening torque of the bolts is between 6.4 and 9.6 N*m (65 and 98 kgf*cm, 57 and 85 in.*lbf).
(d) Check for arc marks at the bolts for the generator cable.
Result:

C -- CONNECT SECURELY
B -- REPLACE MALFUNCTIONING PARTS
A -- Continue to next step.
9. 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.
(b) 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}
NOTE: Make sure that the tightening torque of the bolts is between 6.4 and 9.6 N*m (65 and 98 kgf*cm, 57 and 85 in.*lbf).
(c) Check for arc marks at the bolts for the motor cable.
Result:

C -- CONNECT SECURELY
B -- REPLACE MALFUNCTIONING PARTS
A -- Continue to next step.
10. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (MG1)
CAUTION: Be sure to wear insulated gloves.
(a) Check that the service plug grip is not installed.
(b) Disconnect the generator cable and motor cable from the inverter with converter assembly.
HINT: For the removal and installation procedures related to the generator cable and motor cable, Components.

(c) Check MG1 for an interphase short using a milliohmmeter.
(1) Using a milliohmmeter, measure the resistance according to the value(s) in the table below.
HINT: If the MG1 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:

To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 68° F (20°C).
R20 = Rt / {1 + 0.00393 X (T - 20)}
The calculation is based on the following:
R20: Resistance at 68° F (20°C) (mOhms)
Rt: Measured resistance (mOhms)
T: Temperature when the resistance is measured (°C)
(d) Using a megohmmeter set to 500 V, measure the 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 HYBRID VEHICLE TRANSMISSION ASSEMBLY (GENERATOR CABLE CONNECTION CONDITION)
OK -- Continue to next step.
11. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (MG2)
CAUTION: Be sure to wear insulated gloves.
(a) Check that the service plug grip is not installed.
(b) Disconnect the generator cable and motor cable from the inverter with converter assembly.
HINT: For the removal and installation procedures related to the generator cable and motor cable, Components.

(c) Check MG2 for an interphase short using a milliohmmeter.
(1) Using a milliohmmeter, measure the resistance according to the value(s) in the table below.
HINT: If the 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:

NG -- CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (MOTOR CABLE CONNECTION CONDITION)
OK -- Continue to next step.
12. CHECK CONNECTOR CONNECTION CONDITION (GENERATOR RESOLVER CONNECTOR)

(a) Check the connection of the generator resolver connector.
OK:
The connector is connected securely and there are no contact problems.
NG -- CONNECT SECURELY
OK -- Continue to next step.
13. CHECK CONNECTOR CONNECTION CONDITION (MOTOR RESOLVER CONNECTOR)

(a) Check the connection of the motor resolver connector.
OK:
The connector is connected securely and there are no contact problems.
NG -- CONNECT SECURELY
OK -- REPLACE INVERTER WITH CONVERTER ASSEMBLY
14. CHECK CONNECTOR CONNECTION CONDITION (GENERATOR RESOLVER CONNECTOR)

(a) Check the connection of the generator resolver connector.
OK:
The connector is connected securely and there are no contact problems.
NG -- CONNECT SECURELY
OK -- Continue to next step.
15. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY (MG ECU)-GENERATOR RESOLVER)
(a) Disconnect the generator resolver connector.

(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):

Standard resistance (Check for short):

HINT: The generator resolver is not available separately. If it requires replacement, replace the hybrid vehicle transmission assembly.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY
16. CHECK CONNECTOR CONNECTION CONDITION (MOTOR RESOLVER CONNECTOR)

(a) Check the connection of the motor resolver connector.
OK:
The connector is connected securely and there are no contact problems.
NG -- CONNECT SECURELY
OK -- Continue to next step.
17. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY (MG ECU) - MOTOR RESOLVER)
(a) Disconnect the motor resolver connector.

(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):

Standard resistance (Check for short):

HINT: The motor resolver is not available separately. If it requires replacement, replace the hybrid vehicle transmission assembly.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY
18. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (GENERATOR CABLE CONNECTION CONDITION)

(a) Remove the hybrid vehicle transmission assembly. Components

(b) Check that the bolts for the generator cable are tightened to the specified torque, the generator cable is connected securely, and there are no contact problems.
Specified Condition:
T=8.0 N*m {82 kgf*cm, 71 in.*lbf}
NOTE: Make sure that the tightening torque of the bolts is between 6.4 and 9.6 N*m (65 and 98 kgf*cm, 57 and 85 in.*lbf).
(c) Check for arc marks at the bolts for the generator cable.
Result:

C -- CONNECT SECURELY
B -- REPLACE MALFUNCTIONING PARTS
A -- Continue to next step.
19. CHECK GENERATOR CABLE
(a) Remove the generator cable from the hybrid vehicle transmission assembly. Components

(b) Using a megohmmeter set to 500 V, measure the 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 GENERATOR CABLE
OK -- REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY
20. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (MOTOR CABLE CONNECTION CONDITION)

(a) Remove the hybrid vehicle transmission assembly. Components

(b) 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}
NOTE: Make sure that the tightening torque of the bolts is between 6.4 and 9.6 N*m (65 and 98 kgf*cm, 57 and 85 in.*lbf).
(c) Check for arc marks at the bolts for the motor cable.
Result:

C -- CONNECT SECURELY
B -- REPLACE MALFUNCTIONING PARTS
A -- Continue to next step.
21. CHECK MOTOR CABLE
(a) Remove the motor cable from the hybrid vehicle transmission assembly. Components

NG -- REPLACE MOTOR CABLE
OK -- REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY