GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The amount of current flowing to the solenoid is controlled by the duty ration of the engine control module (ECM) output signal. The higher the duty ratio becomes, the higher the lock-up hydraulic pressure becomes during the lock-up operation.

When an open or short in the shift solenoid valve SLU circuit is detected, the ECM interprets this as a fault. The ECM will turn on the MIL and store the DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2759 Torque Converter Clutch Pressure Control Solenoid Control Circuit Electrical (Shift Solenoid Valve SLU)

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

An open or short is detected in shift solenoid valve SLU circuit for 1 second or more while driving.

Action Taken When the DTC Sets

    • DTC P2759 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. Install a scan tool.
  2. Turn ON the engine.
  3. Select the Activate the Lock Up output control on the scan tool.
  4. While driving the vehicle at 58 km/h (36 mph) or more, use the scan tool to engage the output control to ON.
  5. Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.

Does the engine speed change?

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Go to Step 3

Refer to Testing for Intermittent Conditions and Poor Connections

3

  1. Turn the ignition to OFF.
  2. Disconnect the transmission connector B90.
  3. Measure the resistance as follows:
  4. • Between connector B90 terminals 4 and 9.
    • Between connector B90 terminal 4 and body ground.
    • Between connector B90 terminal 9 and body ground.

Is the resistance measured within specified value?

Between terminals 4 and 9 = 5 to 5.6 Ohms

Between terminal 4 and body ground = 10 Kohms or higher

Between terminal 9 and body ground = 10 Kohms or higher

Go to Step 4

Go to Step 5

4

  1. Connect the transmission connector B90.
  2. Disconnect the ECM connector C19.
  3. Measure the resistance as follows:
  4. • Between connector C19 terminals 57 and terminal 77.
    • Between connector C19 terminal 57 and body ground.
    • Between connector C19 terminal 77 and body ground.

Is the resistance measured within specified value?

Between C19 terminals 57 and 77 = 5 to 5.6 Ohms

Between C19 terminal 57 and body ground = 10 Kohms or higher

Between C19 terminal 77 and body ground = 10 Kohms or higher

Go to Step 9

Go to Step 6

5

  1. Remove the shift solenoid SLU.
  2. Measure the resistance between terminals 1 and 2.
  3. 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 the specified range and can an operating sound be heard when connecting the positive and negative leads?

5 to 5.6 Ohms

Go to Step 7

Go to Step 8

6

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 10

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7

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

Did you complete the repair or replacement?

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Go to Step 10

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8

Replace the shift solenoid valve SLU.

Did you complete the replacement?

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Go to Step 10

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9

Replace the ECM. Refer to Control Module References .

Did you complete the replacement?

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Go to Step 10

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10

  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