GSIC - Global Service Information Center

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

## for Preparation Click here

## 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%

HINT:

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

1. Open or short in shift solenoid valve SL1 circuit
2. Shift solenoid valve SL1
3. 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

## INSPECTION PROCEDURE

HINT:

  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

1.INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL1)

1. Disconnect the E1 wire connector.

1. 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 |

Go to step 3

OK |

2.CHECK WIRE HARNESS (TRANSMISSION WIRE - ECM)

1. Disconnect the E16 ECM connector.

1. 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. Remove the shift solenoid valve SL1.

1. Measure the resistance of the solenoid valve.

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

1. Connect the battery's positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body.

   OK:
     Solenoid makes operating noise.

   HINT:

     Reference: Inspect using an oscilloscope.
     Check the waveform of the ECM connector.

   Standard voltage:
     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