AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0748

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

DESCRIPTION

Changing from 1st to 6th is performed by the ECM turning shift solenoid valves SL1, SL2, SL3, SL4 and SL on and off. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated.

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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) An open or short circuit (output signal duty is 0% or 100%) is detected by the ECM in the shift solenoid valve SL1 circuit while driving and shifting between 4th and 5th gears (SL1 output signal duty is more than 0% and less than 100% under normal conditions) (1-trip detection logic).

  • Open or short in shift solenoid valve SL1 circuit

  • Shift solenoid valve SL1

  • Wiring harness connector

  • ECM

 Comes on DTC stored

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 or off. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. The ECM also performs the fail-safe function and turns the other normal shift solenoid valves on or 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 there is a malfunction.

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WIRING DIAGRAM

A01QQF0E21

CAUTION / NOTICE / HINT

Note

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

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Tech Tips

The following table shows normal operation of shift solenoid valve SL1 when the shift lever is in D:

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

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (SHIFT SOLENOID VALVE SL1 CIRCUIT)


    1. A01QP1NC02
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B77-5 (SL1+) - B77-4 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      B77-5 (SL1+) - Body ground and other terminals Always 10 kΩ or higher
      B77-4 (SL1-) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  2. CHECK HARNESS AND CONNECTOR (WIRING HARNESS CONNECTOR - ECM)


    1. Disconnect the B78 wiring harness connector.

    2. Disconnect the B77 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B78-17 (SL1+) - B77-5 (SL1+) Always Below 1 Ω
      B78-16 (SL1-) - B77-4 (SL1-) Always Below 1 Ω
      B78-17 (SL1+) or B77-5 (SL1+) - Body ground and other terminals Always 10 kΩ or higher
      B78-16 (SL1-) or B77-4 (SL1-) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL1)


    1. A01QRY1C03
      *a

      Component without harness connected

      (Transmission Wire)

      Remove the wiring harness connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A-14 (SL1+) - A-13 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      A-14 (SL1+) - Body ground and other terminals Always 10 kΩ or higher
      A-13 (SL1-) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE WIRING HARNESS CONNECTOR Click here

    NG

  4. INSPECT SHIFT SOLENOID VALVE SL1


    1. A01QTPTC14
      *1 Shift Solenoid Valve SL1

      Remove 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
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE TRANSMISSION WIRE Click here

    NG

    REPLACE SHIFT SOLENOID VALVE SL1 Click here