GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The shift solenoid #2 is energized and de-energized by the powertrain control module (PCM) in response to varying transaxle shift demands. With the shift solenoid #2 de-energized, line pressure is applied to the 1-2 shift valve. With the line pressure applied, the 1-2 shift operates, and the transaxle shifts from second to third gear. When the PCM energizes the shift solenoid #1, line pressure is relieved, and the 1-2 shift valve does not operate.

Conditions for Setting the DTC

    • PCM does not see any voltage drop across the shift solenoid #2 control circuit during the attempted energizing of the solenoid.
    • One driving cycle detection logic

Action Taken When the DTC Sets

A DTC P0758 is stored and the malfunction indicator lamp (MIL) is turned ON.

Diagnostic Aids

Inspect for the following conditions:

    • An open or shorted shift solenoid #2
    • Faulty electrical circuits/open or short to the ground between the shift solenoid #2 and the PCM
    • A faulty PCM

An intermittent may be caused by the following conditions:

    • A poor connection
    • Rubbed through wire insulation
    • A broken wire inside the insulation

Inspect the PCM harness connectors for the following conditions:

    • Backed out terminals
    • Improper mating
    • Broken locks
    • Improperly formed or damaged terminals
    • Inadequate terminal-to-wire connections

Perform the following steps if DTC P0758 cannot be duplicated:

  1. Read the information in the freeze frame data.
  2. Use the data to determine the vehicle operating conditions when the DTC was set.

If any wiring repairs need to be made, refer to Repair Procedures in Electrical Diagnosis.

DTC Confirmation Procedure

  1. Turn the ignition switch to LOCK.
  2. Connect the scan tool to the data link connector (DLC).
  3. Turn the ignition switch to ON.
  4. Use a scan tool to clear the following items from the PCM memory:
  5. • The DTC
    • The pending DTC
    • The freeze frame data
  6. Start the engine.
  7. Step firmly on the brake pedal.
  8. Shift the manual selector to Drive (D).
  9. Leave the selector in Drive (D) for 10 seconds.
  10. Accelerate the vehicle in Drive (D).
  11. Keep driving for 10 seconds at 30 km/h (19 mph).
  12. Stop the vehicle.
  13. Use a scan tool to inspect DTC P0758.

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 inspects the internal coil resistance of the shift solenoid.

  3. This step inspects for a short to ground in BLU wire.

  4. This step inspects for an open in the BLU wire.

  5. This step inspects the condition of the transaxle internal electrical harness for damage.

  6. This step inspects for a short to voltage in the BLU wire.

  7. This step inspects for a poor electrical connection that may have caused the DTC to set.

  8. This step inspects for a faulty PCM.

Step

Action

Value(s)

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  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 within the Freeze Frame conditions as observed.

Does the scan tool display any other DTCs in addition to DTC P0758?

--

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

Go to Step 3

3

  1. Disconnect the transaxle connector.
  2. Use the DMM in order to measure the resistance between the ground and the powertrain control module (PCM) harness connector CZ terminal 14.

Is the resistance equal to the specified value?

Go to Step 4

Go to Step 9

4

Use the DMM in order to measure the resistance between the PCM harness connector CZ terminal 14 and transaxle connector terminal 6.

Is the resistance less than the specified value?

2 ohms

Go to Step 5

Go to Step 10

5

  1. Remove the transaxle oil pan.
  2. Inspect the terminals and the internal harness for damage.
  3. If the terminals and the internal harness are not damaged, replace the shift solenoid #2.

Is the action complete?

--

Go to Step 15

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6

  1. Turn the ignition switch to ON.
  2. Use the DMM in order to measure the voltage between ground and PCM connector CZ terminal 14.

Is the voltage less than the specified value?

2 V

Go to Step 7

Go to Step 11

7

Inspect all of the electrical connections for poor terminal contact or poor connection.

Is poor terminal contact or connection evident?

--

Go to Step 12

Go to Step 8

8

  1. Install a known good PCM. Refer to Powertrain Control Module Programming and Setup in Programming and Setup.
  2. Perform the DTC Confirmation Procedure.

Does DTC P0758 reset?

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Go to Step 14

Go to Step 13

9

Repair the short to ground in the BLU wire between the PCM and the shift solenoid #2.

Is the action complete?

--

Go to Step 15

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10

Repair the open or high resistance in the BLU wire between the PCM and the shift solenoid #2.

Is the action complete?

--

Go to Step 15

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11

Repair the short to voltage in the BLU wire between the PCM and the shift solenoid #2.

Is the action complete?

--

Go to Step 15

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12

Repair the terminals or connections that exhibit poor contact.

Is the action complete?

--

Go to Step 15

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13

Refer to the Diagnostic Aids for a possible intermittent condition. If OK, replace the PCM. Refer to Powertrain Control Module Programming and Setup in Programming and Setup.

Is the action complete?

--

Go to Step 15

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14

Refer to Diagnostic Aids for additional information regarding DTC P0758.

Is the action complete?

--

Go to Step 15

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15

  1. Turn the ignition switch to LOCK.
  2. Reconnect the connectors.
  3. Perform the DTC Confirmation Procedure.

Are any DTCs displayed on the scan tool?

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

System OK