GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 Matiz 🢒 Transmission/Transaxle 🢒 Automatic Transaxle - Jatco 🢒 DTC P0748

Circuit Description

This circuit controls the line pressure solenoid through the transmission control module (TCM). The TCM outputs a duty cycle to control the line pressure. A ground return circuit is necessary for controlling the line pressure with a high level of accuracy.

DTC Descriptor

This diagnostic procedure supports the following DTC: DTC P0748 Pressure Control Solenoid Control Circuit

Conditions for Setting the DTC
    • If the internal data is set as ON, but the port is regarded as Off by the monitor.
    •  Open or short circuit in the wiring harness and/or connector(s).
    • Pressure control solenoid malfunction.
    • Ground return circuit malfunction.
    • TCM malfunction.

Action Taken When the DTC Sets
    • The TCM requests illumination of the malfunction indicator lamp (MIL) and store the DTC when the TCM detects failures on two consecutive driving cycles.
    • Line pressure is maximum.
    • Pressure control solenoid is turned off.

Conditions for Clearing the MIL/DTC

Clear the DTCs with a scan tool.

Conditions for Clearing the DTC
    • A scan tool can clear the DTC.
    • The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
    • The PCM cancels the DTC default actions when the fault no longer exists and the DTC passes.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Automatic Transmission?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2
  1. Turn the ignition OFF.
  2. Disconnect the pressure control solenoid wiring connector and TCM connector.
  3. Check the resistance between the solenoid connector terminal 3 and ground.
  4. Check the resistance between the solenoid connector terminal 5 and ground.

Is the resistance in the specified range?

2.9 ohms 20°C (70°F)

Go to Step 3

Go to Step 5

3
    • Perform a continuity check between the pressure control solenoid connector terminal 3 and the TCM connector Terminal 1.
    • Perform a continuity check between the pressure control solenoid connector terminal 5 and the TCM connector Terminal 2.

Is there continuity?

 

Go to Step 4

Go to Step 5

4

Replace the pressure control solenoid.

Does the pressure control solenoid operate correctly?

--

Go to Step 7

Go to Step 6

5

Repair the wiring harness as necessary. Refer to Wiring Repairs .

Is the action complete?

--

Go to Step 7

--

6

Replace the TCM. Refer to Transmission Control Module Replacement .

Is the action complete?

--

Go to Step 7

--

7
  1. After the repair, use a scan tool clear info function and road test the vehicle.
  2. Review the DTC info.
  3. Observe the DTC Information with a scan tool.

Did the last test fail or is the current DTC displayed?

--

Go to Step 2

System OK