AUTOMATIC TRANSMISSION SYSTEM (for 1UR-FE), Diagnostic DTC:P0748

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

DESCRIPTION

Shifting from 1st to 6th is performed in combination with the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely Click here.

DTC Code DTC Detection Condition Trouble Area
P0748

The ECM 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).

The output signal duty equals 100%.

Tech Tips

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

  • Open or short in shift solenoid valve SL1 circuit

  • Shift solenoid valve SL1

  • ECM

MONITOR DESCRIPTION

This DTC indicates an open or short in the shift solenoid valve SL1 circuit. The ECM 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 ECM detects the problem, illuminates the MIL and stores the DTC. Also, the ECM performs the fail-safe function and turns the other normal shift solenoid valves ON/OFF. In case of an open or short circuit, the ECM stops sending current to the open or short circuited solenoid.

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

WIRING DIAGRAM

A0155BSE14

INSPECTION PROCEDURE

Tech Tips

The shift solenoid valve SL1 turns ON/OFF normally when the shift lever is in D:

ECM gear shift command 1st 2nd 3rd 4th 5th 6th
Shift solenoid valve SL1 OFF OFF OFF OFF ON ON

PROCEDURE


  1. INSPECT NO. 1 TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL1)


    1. A015739E32
      Text in Illustration
      *a

      Component without harness connected

      (No. 1 Transmission Wire)

      Disconnect the No. 1 transmission wire connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      11 (SL1+) - 3 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      11 (SL1+) - Body ground Always 10 kΩ or higher
      3 (SL1-) - Body ground Always 10 kΩ or higher

    NG

    INSPECT SHIFT SOLENOID VALVE SL1 Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (NO. 1 TRANSMISSION WIRE - ECM)

    A015CW9E50
    Text in Illustration
    *1 for LHD
    *2 for RHD
    *a

    Front view of wire harness connector

    (to ECM)

    1. Disconnect the ECM connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      C45-14 (SL1+) - C45-15 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      C45-14 (SL1+) - Body ground Always 10 kΩ or higher
      C45-15 (SL1-) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      C46-14 (SL1+) - C46-15 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      C46-14 (SL1+) - Body ground Always 10 kΩ or higher
      C46-15 (SL1-) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here

  3. INSPECT SHIFT SOLENOID VALVE SL1


    1. A015AF7E11
      Text in Illustration
      *a

      Component without harness connected

      (Shift Solenoid Valve SL1)

      Remove the shift solenoid valve SL1.

    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

    NG

    REPLACE SHIFT SOLENOID VALVE SL1 Click here

    OK

    REPAIR OR REPLACE NO. 1 TRANSMISSION WIRE Click here