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

C239277E21

CAUTION / NOTICE / HINT

Note:

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

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Tip:

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. C267934C02

      *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

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    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. C226545C03

      *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

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    NG

  4. INSPECT SHIFT SOLENOID VALVE SL1

    1. C197715C14

      *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

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    NG

    REPLACE SHIFT SOLENOID VALVE SL1

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