Lexus ES manuals

Lexus ES: Transmission Fluid Temperature Sensor "C" Circuit Short to Ground (P274A11,P274A15)

Lexus ES (XZ10) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Control System (for Nickel Metal Hydride Battery) / Transmission Fluid Temperature Sensor "C" Circuit Short to Ground (P274A11,P274A15)

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:

Hybrid vehicle control ECU malfunction
  • Hybrid vehicle control ECU internal malfunction
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

The resistance of the thermistor built into the transmission fluid temperature sensor changes in accordance with changes in the transmission fluid temperature. The lower the transmission fluid temperature, the higher the thermistor resistance. Conversely, the higher the transmission fluid temperature, the lower the resistance.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P274A11

Transmission Fluid Temperature Sensor "C" Circuit Short to Ground

Short to ground in the transmission fluid temperature sensor circuit

(1 trip detection logic)
  • Wire harness or connector
  • Hybrid vehicle control ECU
  • Hybrid vehicle transaxle assembly (Transmission fluid temperature sensor)

Comes on

Master Warning Light:

Comes on

P274A15

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

Open or short to +B in the transmission fluid temperature sensor circuit

(1 trip detection logic)
  • Wire harness or connector
  • Hybrid vehicle control ECU
  • Hybrid vehicle transaxle assembly (Transmission fluid temperature sensor)

Comes on

Master Warning Light:

Comes on
Related Data List

DTC No.

Data List

P274A11

Transaxle Oil Temperature

P274A15

HINT:

After confirming that DTC P274A11 or P274A15 is output, use the Techstream to check "Transaxle Oil Temperature" in the Data List.

Displayed Temperature

Malfunction

-40°C (-40°F)

Open circuit or short to +B

215°C (419°F)

Short to ground

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

P274C (INF P274A11): Transmission Fluid Temperature Sensor "C" Circuit Low

P274D (INF P274A15): Transmission Fluid Temperature Sensor "C" Circuit High

Required sensors/components

Transmission fluid temperature sensor

Frequency of operation

Continuous

Duration

TMC's intellectual property

MIL operation

1 driving cycle

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not present

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 P274C (INF P274A11) is not detected

DTC P274D (INF P274A15) 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

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

    Click here

  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

PROCEDURE

1.

CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)

Click here

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

2.

CHECK CONNECTOR CONNECTION CONDITION (INTERMEDIATE CONNECTOR)

(a) Check that the intermediate connector which connects the transmission fluid temperature sensor to the hybrid vehicle control ECU is securely connected with no deformation, and that there is no contamination by water or foreign matter.

Click here

HINT:

For vehicles in which the intermediate connector is inside the relay block, check for signs of water intrusion inside the relay block.

OK:

- The connector is connected securely.

- The terminals are not deformed and are connected securely.

- No water or foreign matter in the connectors.

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

3.

CHECK CONNECTOR CONNECTION CONDITION (TRANSMISSION FLUID TEMPERATURE SENSOR CONNECTOR)

(a) Check the connection condition of the transmission fluid temperature sensor connector and the contact pressure of each terminal. Check the terminals for deformation, and check the connector for water ingress and foreign matter.

Click here

OK:

- The connector is connected securely.

- The terminals are not deformed and are connected securely.

- No water or foreign matter in the connector.

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.

READ VALUE USING TECHSTREAM (TRANSAXLE OIL TEMPERATURE)

(a) Connect the Techstream to the DLC3.

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

(c) Enter the following menus: Powertrain / Hybrid Control / Data List / Transaxle Oil Temperature.

Powertrain > Hybrid Control > Data List

Tester Display

Transaxle Oil Temperature

(d) Read the Data List.

Result

Proceed to

-40°C (-40°F)

A

215°C (419°F)

B

Same as actual temperature

C

(e) Turn the power switch off.

B

GO TO STEP 7

C

REPAIR OR REPLACE HARNESS OR CONNECTOR
A

5.

INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (TRANSMISSION FLUID TEMPERATURE SENSOR)

(a) Disconnect the C91 transmission fluid temperature sensor connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C91-3 (TTA) - C91-13 (ETTA)

Power switch off

1.393 to 75.8 kΩ

*a

Component without harness connected

(Transmission Fluid Temperature Sensor (Hybrid Vehicle Transaxle Assembly))

(c) Reconnect the C91 transmission fluid temperature sensor connector.

NG

REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

OK

6.

INSPECT HYBRID VEHICLE CONTROL ECU

(a) Connect terminals 21 (TTA) and 31 (ETTA) of the A32 hybrid vehicle control ECU connector.

*a

Component with harness connected

(Hybrid Vehicle Control ECU)

(b) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Powertrain / Hybrid Control / Data List / Transaxle Oil Temperature.

(e) Read the Data List.

Powertrain > Hybrid Control > Data List

Tester Display

Transaxle Oil Temperature

OK:

Tester Display

Condition

Specified Condition

Transaxle Oil Temperature

Terminals A32-21 (TTA) and A32-31 (ETTA) connected

Power switch on (IG)

215°C (419°F)

(f) Turn the power switch off.

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (TRANSMISSION FLUID TEMPERATURE SENSOR - HYBRID VEHICLE CONTROL ECU)
NG

REPLACE HYBRID VEHICLE CONTROL ECU

7.

INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (TRANSMISSION FLUID TEMPERATURE SENSOR)

(a) Disconnect the C91 transmission fluid temperature sensor connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C91-3 (TTA) - C91-13 (ETTA)

Power switch off

1.393 to 75.8 kΩ

*a

Component without harness connected

(Transmission Fluid Temperature Sensor (Hybrid Vehicle Transaxle Assembly))

(c) Reconnect the C91 transmission fluid temperature sensor connector.

NG

REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

OK

8.

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

(a) Disconnect the C91 transmission fluid temperature sensor connector.

(b) Disconnect the A32 hybrid vehicle control ECU connector.

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

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

C91-3 (TTA) - A32-21 (TTA)

Power switch off

Below 1 Ω

C91-13 (ETTA) - A32-31 (ETTA)

Power switch off

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

C91-3 (TTA) or A32-21 (TTA) - Body ground and other terminals

Power switch off

10 kΩ or higher

C91-13 (ETTA) or A32-31 (ETTA) - Body ground and other terminals

Power switch off

10 kΩ or higher

*a

Front view of wire harness connector

(to Transmission Fluid Temperature Sensor)

*b

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

(d) Reconnect the A32 hybrid vehicle control ECU connector.

(e) Reconnect the C91 transmission fluid temperature sensor connector.

OK

REPLACE HYBRID VEHICLE CONTROL ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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