Lexus ES: 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 |
|---|---|---|---|---|---|
| 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 Light: Comes on |
| DTC No. | Data List |
|---|---|
| P0AA749 | Short Wave Highest Value Level |
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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- Connect the Techstream to the DLC3.
- Turn the power switch on (IG) and turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the power switch off and wait for 2 minutes or more.
- Turn the power switch on (IG) and turn the Techstream on.
- With power switch on (IG) and wait for 70 seconds or more.
- Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.
-
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
| 1. | CLEAR DTC |
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|
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| 2. | SIMULATION TEST |
(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.
Powertrain > Hybrid Control > Trouble Codes| Result | Proceed to |
|---|---|
| P0AA749 is not output. | A |
| P0AA749 is output. | B |
| B | .gif) | REPLACE BATTERY ECU ASSEMBLY |
|
| 3. | SIMULATION TEST |
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.
Powertrain > Hybrid Control > Trouble Codes| Result | Proceed to |
|---|---|
| P0AA649 is not output. | A |
| P0AA649 is output. | B |
| A | | REPLACE BATTERY ECU ASSEMBLY |
| B | | GO TO DTC CHART (P0AA649) |
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Inspection
INSPECTION
PROCEDURE
1. INSPECT NO. 1 HV BATTERY INTAKE FILTER
HINT:
If the vehicle is used in an area with heavy traffic or excessive dust,
or if the rear seat is used frequently, the No. 1 HV battery intake filter
may be clogged. Clean or replace the No. 1 HV battery intake fil
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