Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Hybrid/EV Battery Voltage Isolation Sensor Circuit Internal Electronic Failure (P0AA749)

Toyota Corolla Cross (2022-2025) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Control System / 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 ECU assembly and detects malfunctions.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

Note

P0AA749

Hybrid/EV Battery Voltage Isolation Sensor Circuit Internal Electronic Failure

Malfunction in the insulation monitoring circuit in the battery ECU assembly

(1 trip detection logic)

Battery ECU assembly

Does not come on

Master Warning:

Comes on

SAE Code:

P0AA7

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

  1. Connect the GTS to the DLC3.
  2. Turn the ignition switch to ON and turn the GTS on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the ignition switch off and wait for 2 minutes or more.
  5. Turn the ignition switch to ON and turn the GTS on.
  6. With ignition switch ON 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, perform driving pattern again.

PROCEDURE

1.

CLEAR DTC

Click here

NEXT

2.

SIMULATION TEST

(a) Turn the ignition switch to ON and wait for 70 seconds or more.

NOTICE:

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

(b) Check if DTCs are output.

Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

P0AA749 is not output.

A

P0AA749 is output.

B
B

REPLACE BATTERY ECU ASSEMBLY

A

3.

SIMULATION TEST

NOTICE:

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

(a) With the vehicle and engine stopped, turn the ignition switch to 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) Check if DTCs are output.

Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

P0AA649 is not output.

A

P0AA649 is output.

B

(f) Turn the ignition switch off.

A

REPLACE BATTERY ECU ASSEMBLY

B

GO TO DTC CHART (P0AA649)

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