AUTOMATIC TRANSMISSION SYSTEM, 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 the shift solenoid valves SL1, SL2, S1, S2 and SR, which is controlled by the ECM. If an open or short circuit occurs in the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated safely Click here.

DTC No. DTC Detection Condition Trouble Area
P0748

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

Output signal duty equal to 100%

Tech Tips

SL1 output signal duty is less than 100% under normal condition

  • 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 circuit.

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

A01J6WFE03

INSPECTION PROCEDURE

Tech Tips

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

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

PROCEDURE


  1. INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL1)


    1. A01J5I5E23

      Disconnect the E1 wire connector.

    2. Measure the resistance of the wire connector.

      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 20°C (68°F) 10 kΩ or higher
      4 (SL1-) - Body ground 20°C (68°F) 10 kΩ or higher

    NG

    INSPECT SHIFT SOLENOID VALVE SL1 Click here

    OK

  2. CHECK WIRE HARNESS (TRANSMISSION WIRE - ECM)


    1. A01J5CJE03

      Disconnect the E16 ECM connector.

    2. Measure the resistance of the wire harness side connector.

      Standard resistance
      Tester Connection Condition Specified Condition
      E16-19 (SL1+) - E16-18 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      E16-19 (SL1+) - Body ground 20°C (68°F) 10 kΩ or higher
      E16-18 (SL1-) - Body ground 20°C (68°F) 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE ECM

  3. INSPECT SHIFT SOLENOID VALVE SL1


    1. A01J6TKE16

      Remove the shift solenoid valve SL1.

    2. Measure the resistance of the solenoid valve.

      Standard resistance
      5.0 to 5.6 Ωat 20°C (68°F)

    3. Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve.

    4. Check the operating noise of terminal 1 of the solenoid valve.

      OK
      Solenoid makes operating noise.

      Tech Tips

      Reference: Inspect using an oscilloscope.

      A01J4ENE01

      Check the waveform of the ECM connector.

      OK
      Refer to illustration.
      Item Content
      Tester Connection E16-19 (SL1+) - E16-18 (SL1-)
      Tool Setting 5 V/DIV., 1 msec./DIV.
      Condition Engine idle speed

    NG

    REPLACE SHIFT SOLENOID VALVE SL1

    OK

    REPAIR OR REPLACE TRANSMISSION WIRE