GM Service Manual Online
For 1990-2009 cars only

Object Number: 1778983  Size: LF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Control Module References

Circuit Description

The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves. The solenoid is a normally-open exhaust valve. With the 1-2 SS valve, the 2-3 SS valve allows 4 different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 2-3 SS valve receives voltage through the ignition voltage circuit. The transmission control module (TCM) controls the solenoid by providing the ground path on the 2-3 SS valve control circuit.

When the TCM detects a continuous open, short to ground, in the 2-3 SS valve control circuit, then DTC P0976 sets. DTC P0976 is a type A DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0976 2-3 Shift Solenoid (SS) Control Circuit Low Voltage

Conditions for Running the DTC

    • The engine run time is 5 seconds or greater.
    • The system voltage is between 8-18 volts.

Conditions for Setting the DTC

The TCM detects an open or short to ground in the 2-3 SS valve circuit for 4.4 seconds.

Action Taken When the DTC Sets

    • The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
    • The TCM commands a soft landing to 2nd gear.
    • The TCC commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.
    • The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
    • The TCM stores DTC P0976 in TCM history.

Conditions for Clearing the MIL/DTC

    • The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
    • A scan tool can clear the MIL/DTC.
    • The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.
    • The TCM cancels the default actions when the ignition is OFF long enough in order to power down the TCM.

Test Description

The number below refers to the step number on the diagnostic table.

  1. A short to ground in the ignition 1 voltage circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but, would set the other DTCs.

Step

Action

Value

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the TCM.

  4. Record the Freeze Frame and Failure Records.
  5. Clear the DTCs.

Were DTCs P0973 or P2764 also set?

--

Go to Step 3

Go to Step 9

3

  1. Inspect the fuse in the ignition 1 voltage circuit for an open. Refer to Circuit Testing
  2. Replace the fuse if necessary.

Was the fuse open?

--

Go to Step 4

Go to Step 7

4

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution.

Test the ignition 1 voltage circuit of the 2-3 SS valve for a short to ground between the fuse block and the AT inline 20-way connector. Refer to Testing for Short to Ground .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 5

5

  1. Disconnect the AT wiring harness from the 1-2 SS valve, the 2-3 SS valve and the TCC PWM solenoid valve.
  2. Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution.

  3. Test the ignition 1 voltage circuit of the 2-3 SS valve for a short to ground between the AT inline 20-way connector and the solenoids. Refer to Testing for Short to Ground .

Did you find the condition?

--

Go to Step 17

Go to Step 6

6

  1. Test the 1-2 SS valve, the 2-3 SS valve and the TCC PWM solenoid valve for a short to ground between the ignition 1 voltage side of each solenoid and the transmission case.
  2. Replace any faulty solenoid.

Did you complete the replacement?

--

Go to Step 20

--

7

Test the ignition 1 voltage circuit of the 2-3 SS valve for an open between the fuse block and the AT inline 20-way connector. Refer to Circuit Testing .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 8

8

Test the ignition 1 voltage circuit of the 2-3 SS valve for an open between the AT inline 20-way connector and the solenoid. Refer to Circuit Testing .

Did you find the condition?

--

Go to Step 17

Go to Testing for Intermittent Conditions and Poor Connections

9

  1. Turn OFF the ignition.
  2. Disconnect the AT inline 20-way harness connector. Additional DTCs may set.
  3. Install the J 44152 jumper harness on the engine side of the AT inline 20-way connector.
  4. Using the J 35616 GM-approved terminal test kit, connect a test lamp between the 2-3 SS valve control circuit of the J 44152 and ground.
  5. Refer to Automatic Transmission Inline 20-Way Connector End View .

  6. Turn ON the ignition with the engine OFF.
  7. Using a scan tool, command the 2-3 SS valve ON and OFF three times.

Does the test lamp turn ON and OFF?

--

Go to Step 12

Go to Step 10

10

Test the ignition 1 voltage circuit of the 2-3 SS valve for an open between the fuse block and the AT inline 20-way connector. Refer to Circuit Testing .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 11

11

Test the control circuit of the 2-3 SS valve for an open or a short to ground between the TCM and the AT inline 20-way connector. Refer to Testing for Short to Ground .

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

12

  1. Install the J 44152 on the transmission side of the AT inline 20-way connector.
  2. Using a DMM, measure the resistance of the 2-3 SS valve of the J 44152 .
  3. Refer to Automatic Transmission Inline 20-Way Connector End View .

Does the resistance measure within the specified range?

19-31 ohms

Go to Step 13

Go to Step 16

13

Measure the resistance from both terminals of the 2-3 SS valve to the transmission case.

Are both readings greater than the specified value?

250 K ohms

Go to Step 14

Go to Step 15

14

Measure the resistance on the control side of the 2-3 SS valve and all other terminals of the AT inline 20-way connector. Refer to Testing for Continuity .

Is the resistance less than the specified value?

250 K ohms

Go to Step 16

Go to Testing for Intermittent Conditions and Poor Connections

15

  1. Disconnect the harness from the 2-3 SS valve.
  2. Measure the resistance from each terminal of the solenoid to the transmission case.

Are both readings greater than the specified value?

250 K ohms

Go to Step 17

Go to Step 18

16

  1. Disconnect the harness from the 2-3 SS valve.
  2. Measure the resistance of the solenoid.

Is the resistance within the specified range?

19-31 ohms

Go to Step 17

Go to Step 18

17

Replace the AT wiring harness assembly. Refer to Valve Body and Pressure Switch Replacement .

Did you complete the replacement?

--

Go to Step 20

--

18

Replace the 2-3 SS valve. Refer to Valve Body and Pressure Switch Replacement .

Did you complete the replacement?

--

Go to Step 20

--

19

Replace the TCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 20

--

20

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Drive the vehicle in D4 and ensure the following conditions are met:
  4. • The TCM commands the 2-3 SS valve ON and the 2-3 SS Sol. CKT status parameter displays OK.
    • The TCM commands the 1-2 SS valve OFF and the 2-3 Sol. CKT status parameter displays OK.
    • All conditions are met for 4.3 seconds.
  5. Select Specific DTC.
  6. Enter DTC P0976.

Has the test run and passed?

--

Go to Step 21

Go to Step 2

21

With the scan tool, observe the stored information, capture info, and DTC Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK