Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Inverter Low-voltage Circuit

DESCRIPTION

The cause of the malfunction may be the low-voltage circuit.

Check whether there is an open circuit in the inverter +B low-voltage power source system or a problem in the communication between the hybrid vehicle control ECU and inverter.

Related Parts Check

Area

Inspection

Inverter +B low-voltage power source system check

Check for inverter overcurrent malfunction.

Communication malfunction between hybrid vehicle control ECU and MG-ECU inside inverter with converter assembly

Check for inverter overcurrent malfunction due to communication malfunction.

Check for short to ground in inverter +B low-voltage power source system

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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:

Refer to the precautions before inspecting high voltage circuit.

Click here

NOTICE:

  • After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

    Click here

  • When disconnecting and reconnecting the auxiliary battery

    HINT:

    When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

    Click here

PROCEDURE

1.

CHECK FUSE (PCU NO. 1)

(a) Remove the PCU NO. 1 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

PCU NO. 1 fuse

Always

Below 1 Ω

(c) Install the PCU NO. 1 fuse.

NG

GO TO STEP 5

OK

2.

CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY POWER SOURCE CIRCUIT)

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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the inverter with converter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A187-4 (GND1) - Body ground

Ignition switch off

Below 1 Ω

A187-12 (GND2) - Body ground

Ignition switch off

Below 1 Ω

(d) Connect the cable to the negative (-) auxiliary battery terminal.

(e) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A187-1 (IGC1) - Body ground

Ignition switch ON

Same as auxiliary battery voltage

A187-9 (IGC2) - Body ground

Ignition switch ON

Same as auxiliary battery voltage

NOTICE:

Turning the ignition switch to ON with the inverter with converter assembly connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

(g) Turn the ignition switch off.

(h) Disconnect the cable from the negative (-) auxiliary battery terminal and wait for 2 minutes or more.

(i) Reconnect the inverter with converter assembly connector.

NG

REPAIR OR REPLACE POWER SOURCE CIRCUIT

OK

3.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INVERTER WITH CONVERTER ASSEMBLY)

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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the inverter with converter assembly connector.

(c) Disconnect the hybrid vehicle control ECU connector.

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

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

A187-29 (HMCH) - A192-2 (HMCH)

Ignition switch off

Below 1 Ω

A187-30 (HMCL) - A192-1 (HMCL)

Ignition switch off

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

A187-29 (HMCH) or A192-2 (HMCH) - Body ground and other terminals

Ignition switch off

10 kΩ or higher

A187-30 (HMCL) or A192-1 (HMCL) - Body ground and other terminals

Ignition switch off

10 kΩ or higher

(e) Connect the cable to the negative (-) auxiliary battery terminal.

(f) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A187-29 (HMCH) or A192-2 (HMCH) - Body ground and other terminals

Ignition switch ON

Below 1 V

A187-30 (HMCL) or A192-1 (HMCL) - Body ground and other terminals

Ignition switch ON

Below 1 V

NOTICE:

Turning the ignition switch to ON with the hybrid vehicle control ECU and inverter with converter assembly connectors disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

(h) Turn the ignition switch off.

(i) Disconnect the cable from the negative (-) auxiliary battery terminal and wait for 2 minutes or more.

(j) Reconnect the hybrid vehicle control ECU connector.

(k) Reconnect the inverter with converter assembly connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

CHECK HYBRID VEHICLE CONTROL ECU

(a) Disconnect the hybrid vehicle control ECU connector.

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

*a

Component without harness connected

(Hybrid Vehicle Control ECU)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

A192-1 (HMCL) - A192-2 (HMCH)

Ignition switch off

80 to 170 Ω

(c) Reconnect the hybrid vehicle control ECU connector.

OK

INVERTER LOW-VOLTAGE CIRCUIT NORMAL (PERFORM NEXT STEP FOR REFERENCED DTC)

NG

REPLACE HYBRID VEHICLE CONTROL ECU

5.

CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - PCU FUSE)

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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the inverter with converter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A187-1 (IGC1) - Body ground

Ignition switch off

10 kΩ or higher

A187-9 (IGC2) - Body ground

Ignition switch off

10 kΩ or higher

(d) Reconnect the inverter with converter assembly connector.

NG

GO TO STEP 7

OK

6.

REPLACE INVERTER WITH CONVERTER ASSEMBLY

Click here

NEXT

REPLACE FUSE (PCU NO. 1)

7.

REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT

REPLACE FUSE (PCU NO. 1)

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