GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2009 🢒 Vibe - AWD 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0746

Circuit Description

The engine control module (ECM) uses signals from the vehicle speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th or 5th gear).

The ECM then compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transaxle (clutch, brake or gear etc.).

The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". According to the input shaft revolution, intermediate (counter) shaft revolutions and output shaft revolution, the ECM detects the actual gear position (1st, 2nd, 3rd, 4th or 5th gear position). When the gear position commanded by the ECM and the actual gear position are not the same, the ECM illuminates the MIL and stores the DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0746 Pressure Control Solenoid "A" Performance (Shift Solenoid Valve SL1)

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The ECM commands one gear, but the actual gear is different than the one commanded.

Action Taken When the DTC Sets
    • DTC P0746 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 Control the Shift Position output control on the scan tool.
  4. While driving the vehicle at 50 km/h (31 mph) or more, use the scan tool to engage the output control to shift up or shift down.

Does the gear change as selected by the output control?

--

Refer to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3
  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 4

Go to Step 6

4

Inspect transmission valve body assembly for foreign objects and each valve operates smoothly.

Is transmission valve body operation OK?

--

Go to Step 5

Go to Step 7

5

Inspect torque converter clutch assembly for normal operation.

Is torque converter clutch operation OK?

--

Go to Step 9

Go to Step 8

6

Replace the shift solenoid valve SL1.

Did you complete the replacement?

--

Go to Step 9

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7

Replace the transmission valve body assembly.

Did you complete the replacement?

--

Go to Step 9

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8

Replace the torque converter clutch assembly.

Did you complete the replacement?

--

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?

--

Go to Step 2

System OK