СИСТЕМА АВТОМАТИЧЕСКОЙ ТРАНСМИССИИ, Diagnostic DTC:P0748

DTC Code DTC Name
P0748 Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1)

DESCRIPTION

Shifting from 1st to 5th is performed in combination with the ON and OFF operation of shift solenoid valves SL1, SL2, S1, S2 and SR, which are controlled by the TCM. If an open or short circuit occurs in one of the shift solenoid valves, the TCM controls the remaining normal shift solenoid valves to allow the vehicle to be operated smoothly.

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DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0748 Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1)

The TCM checks for an open or short in the shift solenoid valve SL1 circuit while driving and shifting between 4th and 5th gear (1-trip detection logic).

Output signal duty equals 100%.

Tech Tips

SL1 output signal duty is less than 100% under normal conditions.

  • Open or short in shift solenoid valve SL1 circuit

  • Shift solenoid valve SL1

  • TCM

 Comes on DTC stored

MONITOR DESCRIPTION

This DTC indicates an open or short in the shift solenoid valve SL1 circuit. The TCM commands gear shifts by turning the shift solenoid valves ON/OFF. When there is an open or short circuit in any shift solenoid valve circuit, the TCM detects the problem, illuminates the MIL and stores the DTC. Then the TCM performs the fail-safe function and turns the other normal shift solenoid valves ON/OFF. In the case of an open or short circuit, the TCM stops sending current to the circuit.

While driving and shifting between 4th and 5th gears, if the TCM detects an open or short in the shift solenoid valve SL1 circuit, the TCM determines there is a malfunction.

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WIRING DIAGRAM

A01SBU8E33
*a Shift Solenoid Valve SL1
*b Transmission Wire

CAUTION / NOTICE / HINT

Note

Perform registration and/or initialization when parts related to the automatic transmission are replaced.

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Tech Tips


  • Shift solenoid valve SL1 is turned ON/OFF normally when the shift lever is in D.

    TCM gear shift command 1st 2nd 3rd 4th 5th
    Shift solenoid valve SL1 OFF OFF OFF OFF ON

  • After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


    1. Perform the D Position Shift Test in Road Test.

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    2. Check for DTCs again.

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PROCEDURE


  1. INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL1)


    1. A01SBLUC50
      *a

      Component without harness connected

      (Transmission Wire)

      Disconnect the transmission wire connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      12 (SL1+) - 4 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      12 (SL1+) - Body ground Always 10 kΩ or higher
      4 (SL1-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT SHIFT SOLENOID VALVE SL1 Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - TCM)


    1. A01SDU9C04
      *a

      Rear view of wire harness connector

      (to TCM)

      Disconnect the TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C77-9 (SL1+) - C77-8 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      C77-9 (SL1+) - Body ground Always 10 kΩ or higher
      C77-8 (SL1-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE TCM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  3. INSPECT SHIFT SOLENOID VALVE SL1


    1. A01SK10C22
      *a

      Component without harness connected

      (Shift Solenoid Valve SL1)

      Remove shift solenoid valve SL1.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 - 2 20°C (68°F) 5.0 to 5.6 Ω

    3. Apply 12 V battery voltage to the shift solenoid valve and check that the valve moves and makes an operating noise.

      OK
      Measurement Condition Specified Condition

      • Battery positive (+) with a 21 W bulb → Terminal 1

      • Battery negative (-) → Terminal 2

      		 Valve moves and makes an operating noise
      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE TRANSMISSION WIRE Click here

    NG

    REPLACE SHIFT SOLENOID VALVE SL1 Click here