GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The powertrain control module (PCM) uses signals from the throttle position (TP) sensor to control the line pressure control solenoid by sending a predetermined duty ratio to the solenoid.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1760 Line Pressure Control (PC) Solenoid Control Circuit

Conditions for Setting the DTC

DTC P1760 will set when one of the following conditions are met:

    • SLT--Terminal voltage is 0 volts for 1 second or more.
    • SLT--Terminal voltage is 12 volts for 1 second or more.

Action Taken When the DTC Sets

A DTC P1760 is stored and the malfunction indicator lamp (MIL) is turned ON.

Diagnostic Aids

Inspect for the following conditions:

    • A short between the line pressure control solenoid - high and the line pressure control solenoid - low circuits
    • An open or high resistance between the line pressure control solenoid - high and the line pressure control solenoid - low circuits
    • A short to ground in the line pressure control solenoid - high or the line pressure control solenoid - low circuits
    • A short to ground in the line pressure control solenoid - high or the line pressure control solenoid - low circuits
    • A malfunctioning line pressure control solenoid
    • Faulty PCM

If this DTC cannot be duplicated, the information included in the freeze frame data can be useful in determining vehicle operating conditions when the DTC was first set.

DTC Confirmation Procedure

  1. Turn the ignition switch to LOCK.
  2. Connect the scan tool to data link connector (DLC).
  3. Turn the ignition switch to ON.
  4. Clear the DTC, the pending DTC, and the freeze frame data in PCM memory by using the scan tool.
  5. Start the engine and warm up to normal operating temperature.
  6. Accelerate vehicle in Drive (D) range and drive at 80 km/h (50 mph) for 10 seconds.
  7. Stop the vehicle.
  8. Test for a pending DTC with the scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. The Diagnostic System Check - Vehicle, prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

  2. This step checks for a faulty PCM.

  3. This step checks for a faulty solenoid.

Step

Action

Values

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

Connector End View Reference: Automatic Transmission External Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Does the scan tool display any other DTCs?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Go to Step 3

3

  1. Install a scan tool.
  2. Turn the ignition to ON, leaving the engine OFF.
  3. Perform the scan tool Clear DTC Information function.
  4. Operate the vehicle with the scan tool connected.

Did DTC P1760 reset?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Disconnect the transmission connector.
  2. Measure the resistance between terminals of the line pressure control solenoid at transmission connector.

Is the resistance as specified?

5.1-5.5 ohms at 20°C (68°F)

Go to Step 5

Go to Step 6

5

  1. Connect the transmission connector.
  2. Disconnect the powertrain control module (PCM) connector.
  3. Measure the resistance between terminals of the line pressure control solenoid circuit.

Is the resistance as specified?

5.1-5.5 ohms at 20°C (68°F)

Go to Step 7

Go to Step 8

6

  1. Remove the line pressure control solenoid. Refer to Solenoids and Wiring Harness Replacement .
  2. Connect a positive test lead with a inline 21-watt bulb to terminal 2 of the solenoid and a negative test lead to terminal 1.
  3. Solenoid should move downward when voltage is applied and upward when voltage is removed.

Does the solenoid operate as described?

--

Go to Step 9

Go to Step 10

7

Replace PCM. Refer to Powertrain Control Module Programming and Setup in Programming and Setup.

Is the repair complete?

--

Go to Step 11

--

8

Test the line pressure control solenoid circuit for an open, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

--

9

Repair or replace transmission wiring harness. Refer to Solenoids and Wiring Harness Replacement .

Is the repair complete?

--

Go to Step 11

--

10

Replace the line pressure control solenoid. Refer to Solenoids and Wiring Harness Replacement .

Is the repair complete?

--

Go to Step 11

--

11

Perform the DTC Confirmation Procedure.

Are any DTCs displayed on the scan tool?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

System OK