Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Hybrid/EV Battery Voltage Isolation Sensor Circuit Internal Electronic Failure (P0AA749)

DESCRIPTION

The hybrid vehicle control ECU monitors the insulation monitoring circuit located in the battery voltage sensor and detects malfunctions.

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.

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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 70 seconds or more.
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 driving pattern again.

PROCEDURE

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NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and wait for 70 seconds or more.

NOTICE:

Do not turn the power switch off until step 3 is complete.

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

(d) Check if DTCs are output.

B

REPLACE BATTERY VOLTAGE SENSOR

A

NOTICE:

Do not turn the power switch off while performing this inspection.

(a) With the vehicle and engine stopped, turn the power switch on (READY) with shift lever in P and wait for 70 seconds or more. (If the engine starts, wait until the engine stops.)

(b) While depressing the brake pedal without depressing the accelerator pedal, move the shift lever to D and wait for 1 minute. (Step A)

(c) Drive the vehicle 0.5 m (1.6 ft.) forward and perform step A.

(d) Drive the vehicle another 0.5 m (1.6 ft.) forward and perform step A. Repeat this procedure 5 times (minimum total driving distance: 2 m (6.6 ft.)).

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

(f) Check if DTCs are output.

A

REPLACE BATTERY VOLTAGE SENSOR

B

GO TO DTC CHART (P0AA649)