Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: 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.

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:

• Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.
  • Inspecting the high-voltage system
  • Disconnecting the low voltage connector of the inverter with converter assembly
  • Disconnecting the low voltage connector of the HV battery
• To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.
• After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
• After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.

  *a	Without waiting for 10 minutes

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  HINT:

  Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

NOTICE:

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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PROCEDURE

(a) Remove the PCU fuse from the No. 4 relay block.

*1 No. 4 Relay Block *2 PCU Fuse

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

Standard Resistance:

(c) Install the PCU fuse.

NG

GO TO STEP 5

OK

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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the A42 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 A42-24 (GND1) - Body ground Power switch off Below 1 Ω A42-23 (GND2) - Body ground Power switch off Below 1 Ω

*a Front view of wire harness connector (to Inverter with Converter Assembly)

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

(e) Turn the power switch on (IG).

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

Standard Voltage:

NOTICE:

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

(g) Turn the power switch off.

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

(i) Reconnect the A42 inverter with converter assembly connector.

NG

REPAIR OR REPLACE POWER SOURCE CIRCUIT

OK

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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the A42 inverter with converter assembly connector.

(c) Disconnect the A24 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 A42-20 (HMCH) - A24-31 (HMCH) Power switch off Below 1 Ω A42-19 (HMCL) - A24-30 (HMCL) Power switch off Below 1 Ω Standard Resistance (Check for Short): Tester Connection Condition Specified Condition A42-20 (HMCH) or A24-31 (HMCH) - Body ground and other terminals Power switch off 10 kΩ or higher A42-19 (HMCL) or A24-30 (HMCL) - Body ground and other terminals Power switch off 10 kΩ or higher

*a Front view of wire harness connector (to Inverter with Converter Assembly) *b Rear view of wire harness connector (to Hybrid Vehicle Control ECU)

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

(f) Turn the power switch on (IG).

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

Standard Voltage:

NOTICE:

Turning the power switch on (IG) 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 power switch off.

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

(j) Reconnect the A24 hybrid vehicle control ECU connector.

(k) Reconnect the A42 inverter with converter assembly connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Disconnect the A24 hybrid vehicle control ECU connector.

(b) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition A24-30 (HMCL) - A24-31 (HMCH) Power switch off 80 to 170 Ω

*a Component without harness connected (Hybrid Vehicle Control ECU)

(c) Reconnect the A24 hybrid vehicle control ECU connector.

OK

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

NG

REPLACE HYBRID VEHICLE CONTROL ECU

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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the A42 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 A42-6 (+B) - Body ground Power switch off 10 kΩ or higher A42-5 (+B2) - Body ground Power switch off 10 kΩ or higher

*a Front view of wire harness connector (to Inverter with Converter Assembly)

(d) Reconnect the A42 inverter with converter assembly connector.

NG

GO TO STEP 7

OK

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NEXT

REPLACE FUSE (PCU)

NEXT

REPLACE FUSE (PCU)