Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001RHDY
Model Year Start: 2021 Model: Avalon HV Prod Date Range: [08/2020 -           ]
Title: HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P274A1C,P274A1F; Transmission Fluid Temperature Sensor "C" Voltage Out of Range; 2021 - 2022 MY Avalon HV [08/2020 -        ]

DTC

P274A1C

Transmission Fluid Temperature Sensor "C" Voltage Out of Range

DTC

P274A1F

Transmission Fluid Temperature Sensor "C" Circuit Intermittent

DTC SUMMARY

MALFUNCTION DESCRIPTION

These DTCs are stored when the transmission fluid temperature sensor output is abnormal. The cause of this malfunction may be one of the following:

Transmission fluid temperature sensor malfunction

  • Internal transmission fluid temperature sensor malfunction
  • Open or short in transmission fluid temperature sensor

Wire harness between the transmission fluid temperature sensor and hybrid vehicle control ECU

  • The connectors are not connected properly
  • Foreign matter or water on the connector terminals
  • Open or short in wire harness

DESCRIPTION

Refer to the description for DTC P274A11.

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P274A11,P274A15; Transmission Fluid Temperature Sensor "C" Circuit Short to Ground+

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P274A1C

Transmission Fluid Temperature Sensor "C" Voltage Out of Range

After a long soak, the value of the transmission fluid temperature sensor is different from the value of the other temperature sensors.

(2 trip detection logic)

  • Wire harness or connector
  • Hybrid vehicle transaxle assembly (Transmission fluid temperature sensor)

Comes on

Master Warning Light:

Comes on

P274A1F

Transmission Fluid Temperature Sensor "C" Circuit Intermittent

Sudden change in transmission fluid temperature sensor output or hunting:

Unusual sudden change in transmission fluid temperature sensor output occurs and offset condition continues for a certain period of time, or unusual change in transmission fluid temperature sensor output occurs repeatedly.

(1 trip detection logic)

  • Wire harness or connector
  • Hybrid vehicle transaxle assembly (Transmission fluid temperature sensor)

Comes on

Master Warning Light:

Comes on

Related Data List

DTC No.

Data List

P274A1C

  • Generator Temperature
  • Motor Temperature
  • Transaxle Oil Temperature

P274A1F

Transaxle Oil Temperature

MONITOR DESCRIPTION

If the hybrid vehicle control ECU detects a malfunction of the transmission fluid temperature sensor, it will illuminate the MIL and store a DTC.

MONITOR STRATEGY

Related DTCs

P274B (INF P274A1C): Transmission Fluid Temperature Sensor "C" Circuit Range/Performance

P274E (INF P274A1F): Transmission Fluid Temperature Sensor "C" Circuit Intermittent

Required sensors/components

Transmission fluid temperature sensor

Frequency of operation

Continuous

Duration

TMC's intellectual property

MIL operation

2 driving cycles / 1 driving cycle

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not stored

TMC's intellectual property

Other conditions belong to TMC's intellectual property

-

TYPICAL MALFUNCTION THRESHOLDS

TMC's intellectual property

-

COMPONENT OPERATING RANGE

Hybrid vehicle control ECU

DTC P274B (INF P274A1C) is not detected

DTC P274E (INF P274A1F) is not detected

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

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

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

DTC P274A1C

  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.
  5. Leave the vehicle as is for 5 hours or more and then check the values of the Data List items "Generator Temperature", "Motor Temperature" and "Transaxle Oil Temperature". [*1]
  6. Turn the power switch on (IG) and turn the Techstream on. [*2]

    HINT:

    [*1] to [*2]: 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.

DTC P274A1F

  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 5 seconds or more. [*1]

    HINT:

    [*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

Refer to the wiring diagram for DTC P274A11.

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P274A11,P274A15; Transmission Fluid Temperature Sensor "C" Circuit Short to Ground+

PROCEDURE

1.

CHECK DTC OUTPUT (ENGINE)

(a) Connect the Techstream to the DLC3.

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

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

(d) Check for DTCs.

Powertrain > Engine > Trouble Codes

Result

Proceed to

No DTCs are output, or DTCs except the ones in the table below are also output.

A

Any of the following DTCs are also output.

B

Relevant DTC

P261029

ECM/PCM Engine Off Timer Performance Signal Invalid

(e) Turn the power switch off.

B

GO TO DTC CHART (SFI SYSTEM) 2021 MY Avalon HV [08/2020 - 08/2021]; A25A-FXS (ENGINE CONTROL): SFI SYSTEM: DIAGNOSTIC TROUBLE CODE CHART 2022 MY Avalon HV [08/2021 -        ]; A25A-FXS (ENGINE CONTROL): SFI SYSTEM: DIAGNOSTIC TROUBLE CODE CHART

A

2.

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

No DTCs are output, or DTCs except the ones in the table below are also output

A

Any of the following DTCs are also output

B

Relevant DTC

P274A11

Transmission Fluid Temperature Sensor "C" Circuit Short to Ground

P274A15

Transmission Fluid Temperature Sensor "C" Circuit Short to Auxiliary Battery or Open

(e) Turn the power switch off.

B

GO TO DTC CHART (HYBRID CONTROL SYSTEM) 2021 MY Avalon HV [08/2020 - 08/2021]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): DIAGNOSTIC TROUBLE CODE CHART 2022 MY Avalon HV [08/2021 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): DIAGNOSTIC TROUBLE CODE CHART

A

3.

CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P0A2A11,P0A2A15; Drive Motor "A" Temperature Sensor Circuit Short to Ground+

Result

Proceed to

OK

A

NG (The connector is not connected securely.)

B

NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.)

C

B

CONNECT SECURELY

C

REPAIR OR REPLACE HARNESS OR CONNECTOR

A

4.

CHECK HARNESS AND CONNECTOR (TRANSMISSION FLUID TEMPERATURE SENSOR - HYBRID VEHICLE CONTROL ECU)

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A23-21 (TTA) - A23-31 (ETTA)

Power switch off

1.393 to 75.8 kΩ

*a

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

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

NG

GO TO STEP 9

OK

5.

CHECK CONNECTOR CONNECTION CONDITION (INTERMEDIATE CONNECTOR)

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P274A11,P274A15; Transmission Fluid Temperature Sensor "C" Circuit Short to Ground+

Result

Proceed to

OK

A

NG (The connector is not connected securely.)

B

NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.)

C

B

CONNECT SECURELY

C

REPAIR OR REPLACE HARNESS OR CONNECTOR

A

6.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the CA4 No. 1 engine room relay block and No. 1 junction block assembly connector.

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

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

HINT:

When performing the measurement, lightly jiggle the wire harness up and down and left and right and confirm that the resistance does not fluctuate.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

CA4-2 (TTA) - A23-21 (TTA)

Power switch off

Below 1 Ω

CA4-3 (ETTA) - A23-31 (ETTA)

Power switch off

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

CA4-2 (TTA) or A23-21 (TTA) - Body ground and other terminals

Power switch off

10 kΩ or higher

CA4-3 (ETTA) or A23-31 (ETTA) - Body ground and other terminals

Power switch off

10 kΩ or higher

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

(e) Reconnect the CA4 No. 1 engine room relay block and No. 1 junction block assembly connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.

CHECK CONNECTOR CONNECTION CONDITION (TRANSMISSION FLUID TEMPERATURE SENSOR CONNECTOR)

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P274A11,P274A15; Transmission Fluid Temperature Sensor "C" Circuit Short to Ground+

Result

Proceed to

OK

A

NG (The connector is not connected securely.)

B

NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.)

C

B

CONNECT SECURELY

C

REPAIR OR REPLACE HARNESS OR CONNECTOR

A

8.

CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - TRANSMISSION FLUID TEMPERATURE SENSOR)

(a) Disconnect the C63 transmission fluid temperature sensor connector.

(b) Disconnect the CA4 No. 1 engine room relay block and No. 1 junction block assembly connector.

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

HINT:

When performing the measurement, lightly jiggle the wire harness up and down and left and right and confirm that the resistance does not fluctuate.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

CA4-2 (TTA) - C63-3 (TTA)

Power switch off

Below 1 Ω

CA4-3 (ETTA) - C63-13 (ETTA)

Power switch off

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

CA4-2 (TTA) or C63-3 (TTA) - Body ground and other terminals

Power switch off

10 kΩ or higher

CA4-3 (ETTA) or C63-13 (ETTA) - Body ground and other terminals

Power switch off

10 kΩ or higher

(d) Reconnect the CA4 No. 1 engine room relay block and No. 1 junction block assembly connector.

(e) Reconnect the C63 transmission fluid temperature sensor connector.

OK

REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; P710 (HYBRID TRANSMISSION / TRANSAXLE): HYBRID VEHICLE TRANSAXLE: REMOVAL 2022 MY Avalon HV [08/2021 -        ]; P710 (HYBRID TRANSMISSION / TRANSAXLE): HYBRID VEHICLE TRANSAXLE: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.

INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (TRANSMISSION FLUID TEMPERATURE SENSOR)

(a) Disconnect the CA4 No. 1 engine room relay block and No. 1 junction block assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

CA4-2 (TTA) - CA4-3 (ETTA)

Power switch off

1.393 to 75.8 kΩ

(c) Reconnect the CA4 No. 1 engine room relay block and No. 1 junction block assembly connector.

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY)

NG

10.

INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (TRANSMISSION FLUID TEMPERATURE SENSOR)

Click here 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): P274A11,P274A15; Transmission Fluid Temperature Sensor "C" Circuit Short to Ground+

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - TRANSMISSION FLUID TEMPERATURE SENSOR)

NG

REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; P710 (HYBRID TRANSMISSION / TRANSAXLE): HYBRID VEHICLE TRANSAXLE: REMOVAL 2022 MY Avalon HV [08/2021 -        ]; P710 (HYBRID TRANSMISSION / TRANSAXLE): HYBRID VEHICLE TRANSAXLE: REMOVAL