Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Drive Motor "A" Control Module Unexpected Operation (P0A1B94)

DTC SUMMARY

MALFUNCTION DESCRIPTION

The hybrid vehicle control ECU monitors the motor generator control ECU (MG ECU).

The cause of this malfunction may be the following:

• Motor generator control ECU (MG ECU) malfunction

DESCRIPTION

The hybrid vehicle control ECU monitors the motor generator control ECU (MG ECU) and stores this DTC when it detects a malfunction.

MONITOR DESCRIPTION

The hybrid vehicle control ECU monitors the motor generator control ECU (MG ECU). If the internal operation is malfunctioning, the hybrid vehicle control ECU illuminates the MIL and stores a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

CONFIRMATION DRIVING PATTERN

HINT:

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

  Click here

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

  Click here

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:

   • If the vehicle has returned to normal, it can be driven after turning the power switch on (READY).
   • [*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

CAUTION / NOTICE / HINT

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.

Click here

PROCEDURE

(a) Check the connection of the negative (-) and positive (+) auxiliary battery terminals.

OK:

The terminals are connected securely and there is no contact problem.

HINT:

If performing a reproduction test, turn the power switch on (IG) and shake the wire harnesses vertically and horizontally before checking for DTCs.

NG

GO TO STEP 6

OK

(a) Check the installation condition of the ground wires MA. OK: The ground wires MA are securely installed. HINT: If performing a reproduction test, turn the power switch on (IG) and shake the wire harnesses vertically and horizontally before checking for DTCs.

NG

GO TO STEP 7

OK

(a) Disconnect the cable from the negative (-) auxiliary battery terminal.

(b) Disconnect the cable from the positive (+) auxiliary battery terminal.

(c) Check the fusible link block assembly (IGCT) for improper installation.

OK:

The fusible link block assembly is installed securely and there is no contact problem.

(d) Disconnect the 7B fusible link block assembly connector.

(e) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition 7B-1 - A-1 (Positive (+) auxiliary battery terminal) Power switch off Below 1 Ω

*1 Fusible Link Block Assembly *a Component without harness connected (Fusible Link Block Assembly)

(f) Reconnect the 7B fusible link block assembly connector.

(g) Reconnect the cable from the positive (+) auxiliary battery terminal.

(h) Reconnect the cable from the negative (-) auxiliary battery terminal.

NG

GO TO STEP 8

OK

(a) Check the IGCT relay for improper installation.

OK:

The relay is installed securely.

HINT:

If performing a reproduction test, turn the power switch on (IG) and gently vibrate the IGCT relay with a finger before checking for DTCs.

(b) Remove the IGCT relay from the No. 3 relay block.

*1 No. 3 Relay Block *2 IGCT Relay

(c) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition 3 - 5 Auxiliary battery voltage not applied between terminals 1 and 2 10 kΩ or higher Auxiliary battery voltage applied between terminals 1 and 2 Below 1 Ω

*1 IGCT Relay

(d) Install the IGCT relay.

NG

GO TO STEP 9

OK

(a) Connect the Techstream to the DLC3.

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

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

(d) Check for DTCs.

HINT:

Check the DTCs that were output when the vehicle was brought to the workshop.

(e) Turn the power switch off.

A

REPLACE INVERTER WITH CONVERTER ASSEMBLY

B

GO TO DTC CHART (HYBRID CONTROL SYSTEM)

NEXT

GO TO STEP 10

NEXT

GO TO STEP 10

NEXT

GO TO STEP 10

NEXT

Click here

NEXT

(a) Turn the power switch off and wait for 2 minutes or more.

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

(c) Turn the power switch off.

NEXT

(a) Connect the Techstream to the DLC3.

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

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

(d) Check for DTCs.

(e) Turn the power switch off.

A

END

B

REPLACE INVERTER WITH CONVERTER ASSEMBLY

C

GO TO DTC CHART (HYBRID CONTROL SYSTEM)