Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001RISQ
Model Year Start: 2021 Model: Avalon HV Prod Date Range: [08/2020 -           ]
Title: HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P253012; IG2 Signal Circuit Short to Auxiliary Battery; 2021 - 2022 MY Avalon HV [08/2020 -        ]

DTC

P253012

IG2 Signal Circuit Short to Auxiliary Battery

DESCRIPTION

The hybrid vehicle control ECU compares the IG2 signal to the IG control status signal sent from the certification ECU (smart key ECU assembly) to detect a stuck on malfunction of the IG2 signal.

HINT:

If DTC P253012 is stored, the power switch will turn off (READY off).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P253012

IG2 Signal Circuit Short to Auxiliary Battery

The IG2 signal of the hybrid vehicle control ECU and the IG control status signal sent from the certification ECU (smart key ECU assembly) do not match.

(1 trip detection logic)
  • Auxiliary battery
  • Certification ECU (smart key ECU assembly)
  • Hybrid vehicle control ECU
  • ECM
  • IG2 NO. 1 relay
  • Wire harness or connector

Does not come on

Master Warning Light:

Comes on

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.

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): UTILITY

  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 wait for 15 seconds or more.
  6. Turn the power switch off and wait for 2 minutes or more.
  7. Turn the power switch on (IG) and turn the Techstream on.
  8. Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.
  9. 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.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Before replacing the certification ECU (smart key ECU assembly), refer to Registration.

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION

PROCEDURE

1.

CHECK AUXILIARY BATTERY VOLTAGE

(a) Turn the power switch off and turn on the high beam headlights for 30 seconds. This will remove the surface charge from the auxiliary battery.

(b) Measure the auxiliary battery voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

Positive (+) auxiliary battery terminal - Negative (-) auxiliary battery terminal

20°C (68°F), Power switch off

12.0 V or higher
OK

GO TO STEP 3

NG

2.

CHARGE OR REPLACE AUXILIARY BATTERY

(a) Charge or replace the auxiliary battery.

NEXT

3.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

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

(e) Clear the DTCs.

Powertrain > Hybrid Control > Clear DTCs

(f) Turn the power switch off.

NEXT

4.

CHECK DTC OUTPUT (HYBRID CONTROL)

(a) Turn the power switch on (IG) and wait for 15 seconds or more.

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

(c) Connect the Techstream to the DLC3.

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

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

Powertrain > Hybrid Control > Trouble Codes

(f) Check for DTCs.

Result

Proceed to

P253012 is output.

A

P253012 is not output.

B

(g) Turn the power switch off.

B

CHECK FOR INTERMITTENT PROBLEMS

A

5.

CHECK DTC OUTPUT (HYBRID CONTROL)

(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.

Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

U012987, U014087, U015187, U016487, U110787 or U117087 is output

A

Other than above

B

(e) Turn the power switch off.

B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL

A

6.

CHECK HYBRID VEHICLE CONTROL ECU

(a) Disconnect the A23 and G46 hybrid vehicle control ECU connectors.

*a

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

(b) Measure the voltage according to the value(s) in the table below.

Condition:

Tester Connection

Condition

A23-3 (IG2) - G46-5 (E01)

Power switch off

(c) Reconnect the A23 and G46 hybrid vehicle control ECU connectors.

Result

Proceed to

9 V or higher

A

Below 9 V

B
B

REPLACE HYBRID VEHICLE CONTROL ECU 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL 2022 MY Avalon HV [08/2021 -        ]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL

A

7.

CHECK ECM

(a) Disconnect the A23 and G46 hybrid vehicle control ECU connectors.

*a

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

(b) Disconnect the A19 ECM connector.

(c) Measure the voltage according to the value(s) in the table below.

Condition:

Tester Connection

Condition

A23-3 (IG2) - G46-5 (E01)

Power switch off

(d) Reconnect the A19 ECM connector.

(e) Reconnect the A23 and G46 hybrid vehicle control ECU connectors.

Result

Proceed to

9 V or higher

A

Below 9 V

B
B

REPLACE ECM 2021 MY Avalon HV [08/2020 - 08/2021]; A25A-FXS (ENGINE CONTROL): ECM: REMOVAL 2022 MY Avalon HV [08/2021 -        ]; A25A-FXS (ENGINE CONTROL): ECM: REMOVAL

A

8.

INSPECT RELAY (IG2 NO. 1)

(a) Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

IG2 NO. 1 Relay

(b) 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

(c) Reinstall the IG2 NO. 1 relay.

NG

REPLACE RELAY (IG2 NO. 1)
OK

9.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - IG2 NO. 1 RELAY)

(a) Disconnect the A23 hybrid vehicle control ECU connector.

(b) Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

A23-3 (IG2) - Body ground

Power switch off

1 V or less

*a

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

(d) Reinstall the IG2 NO. 1 relay.

(e) Reconnect the A23 hybrid vehicle control ECU connector.

OK

(a) Check for intermittent problems.

Click here CHECK FOR INTERMITTENT PROBLEMS

(1) Check the connection and terminal contact pressure of the connectors and wire harnesses between the hybrid vehicle control ECU and the IG2 NO. 1 relay.

(2) When the power switch is on (READY), jiggle the connectors and wire harnesses between the hybrid vehicle control ECU and the IG2 NO. 1 relay.
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR