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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2009 🢒 Vibe - FWD 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0748

Circuit Description

Shifting from 1st to 5th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, SL3, S4 and SR which are controlled by the engine control module (ECM). If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly (fail safe function). The ECM will illuminate the MIL and store the DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

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

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The ECM detects an open or short in the shift solenoid valve SL1 circuit.

Action Taken When the DTC Sets
    • DTC P0748 is a type C DTC.
    • The malfunction indicator lamp (MIL) illuminates the first time the diagnostic runs with the fault active.

Conditions for Clearing the MIL/DTC

The DTC will clear when conditions for setting the DTC have been repaired.

Step

Action

Values

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn the ignition to OFF.
  2. Disconnect the transmission connector C25.
  3. Measure the resistance as follows:
    4. • Between connector C25 terminals 6 and 13.
    • Between connector C25 terminal 6 and body ground.
    • Between connector C25 terminal 13 and body ground.

Is the resistance measured within specified value?

Between terminals 6 and 13 = 5 to 5.6 Ohms

Between terminal 6 and body ground = 10 Kohms or higher

Between terminal 13 and body ground = 10 Kohms or higher

Go to Step 3

Go to Step 4

3
  1. Connect the transmission connector C25.
  2. Disconnect the ECM connector C24.
  3. Measure the resistance as follows:
    4. • Between connector C24 terminal 57 and terminal 77.
    • Between connector C24 terminal 57 and body ground.
    • Between connector C24 terminal 77 and body ground.

Is the resistance measured within specified value?

Between terminals 11 and 10 = 5 to 5.6 Ohms

Between C24 terminal 57 and body ground = 10 Kohms or higher

Between C24 terminal 77 and body ground = 10 Kohms or higher

Go to Step 8

Go to Step 5

4
  1. Turn the ignition to OFF.
  2. Remove the shift solenoid valve SL1.
  3. Measure the resistance between terminals 1 and 2 of the solenoid valve connector.
  4. Connect the positive lead with a 21 watt bulb to terminal 2 and the negative lead to terminal 1 of the solenoid valve connector, then check the movement of the valve.

Is the resistance measured within specified value and does the solenoid make an operating sound?

5 to 5.6 Ohms

Go to Step 6

Go to Step 7

5

Repair or replace harness or connector of the ECM. Refer to Wiring Repairs and Connector Repairs.

Did you complete the repair or replacement?

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Go to Step 9

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6

Repair or replace harness or connector of the shift solenoid valve SL1. Refer to Wiring Repairs and Connector Repairs.

Did you complete the repair or replacement?

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Go to Step 9

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7

Replace the shift solenoid valve SL1.

Did you complete the replacement?

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Go to Step 9

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8

Replace the ECM. Refer to Control Module References.

Did you complete the replacement?

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Go to Step 9

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9
  1. Use the scan tool in order to clear the DTC.
  2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

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Go to Step 2

System OK