Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message (P312387)

DESCRIPTION

For a description of the inverter.

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The MG ECU, which is built into in the inverter with converter assembly, controls motor (MG2) based on commands from the hybrid vehicle control ECU. The MG ECU monitors communication data and detects malfunctions.

The hybrid vehicle control ECU monitors communication data and detects malfunctions.

A communication error between the MG ECU and the hybrid vehicle control ECU.

MONITOR DESCRIPTION

The hybrid vehicle control ECU monitors communication data and detects malfunctions, it will illuminate the MIL and store a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

CONFIRMATION DRIVING PATTERN

HINT:

• After repair has been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

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• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

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1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG) and turn the Techstream on.
3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
4. Turn the power switch off and wait for 2 minutes or more.
5. Turn the power switch on (IG) and turn the Techstream on.
6. With power switch on (IG) and wait for 2 minutes or more.[*1]

   HINT:

   [*1] : Normal judgment procedure.

   The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

7. Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.
8. Check the DTC judgment result.

   HINT:

   • If the judgment result shows NORMAL, the system is normal.
   • If the judgment result shows ABNORMAL, the system has a malfunction.
   • If the judgment result shows INCOMPLETE or N/A, perform the normal judgment procedure again.

WIRING DIAGRAM

Refer to the wiring diagram for the inverter low-voltage circuit.

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CAUTION / NOTICE / HINT

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.

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  *a	Without waiting for 10 minutes

  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.

(b) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition PCU fuse Always Below 1 Ω

*1 No. 4 Relay Block *2 PCU Fuse

(c) Install the PCU fuse.

NG

GO TO STEP 9

OK

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NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and wait for 2 minutes or more.

(c) Enter the following menus: Powertrain / Hybrid Control / Utility / Diagnosis Related Information.

(d) Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

(e) Check for DTCs.

(f) Turn the power switch off.

B

CHECK FOR INTERMITTENT PROBLEMS

A

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NG

CONNECT SECURELY

OK

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B

CONNECT SECURELY

C

REPAIR OR REPLACE HARNESS OR CONNECTOR

A

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 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 HARNESS OR CONNECTOR

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) 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: Tester Connection Condition Specified Condition A24-30 (HMCL) - Body ground Power switch on (IG) Below 1 V A24-31 (HMCH) - Body ground Power switch on (IG) Below 1 V NOTICE: Turning the power switch on (IG) with the hybrid vehicle control ECU connector and the inverter with converter assembly disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

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

(g) Turn the power switch off.

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

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

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

(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

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 A24-30 (HMCL) -A24-31 (HMCH) Power switch off 110 to 130 Ω

*a Component with harness connected (Hybrid Vehicle Control ECU)

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

OK

REPLACE INVERTER WITH CONVERTER ASSEMBLY

NG

REPLACE HYBRID VEHICLE CONTROL ECU

(a) Replace the PCU fuse.

*1 No. 4 Relay Block *2 PCU Fuse

(b) Turn the power switch on (READY).

(c) Check if there is an open circuit in the PCU fuse in the No. 4 relay block.

OK:

There is no open circuit in the PCU fuse.

HINT:

If the fuse does not become open again after turning the power switch on (READY), it can be assumed that the previous fuse failed due to age.

(d) Turn the power switch off.

OK

END

NG

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

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

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

Standard Resistance (Check for Short):

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

(f) Install the PCU fuse.

NG

GO TO STEP 12

OK

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NEXT

REPLACE FUSE (PCU)

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REPLACE FUSE (PCU)