GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Holden 🢒 2005 🢒 Commodore Executive 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L60-E/4L65-E 🢒 DTC P0973

DTC P0973 V6

DTC Description

This diagnostic procedure supports DTC P0973 1-2 Shift Solenoid (SS) Control Circuit Low Voltage.

Circuit Description

The 1-2 shift solenoid (SS) valve controls the fluid acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows four different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 1-2 SS valve receives ignition voltage through the ignition 1 voltage circuit (circuit 339). The transmission control module (TCM) controls the solenoid by providing the ground path on the 1-2 SS valve control circuit (circuit 1222).

When the TCM detects a continuous open or short to ground in the 1-2 SS valve circuit, then DTC P0973 sets. DTC P0973 is a type B DTC.

Refer to Automatic Transmission Controls Schematics , Automatic Transmission Inline 20-Way Connector End View , Automatic Transmission Internal Connector End Views , Automatic Transmission Control Module Connector End Views , and Automatic Transmission Related Connector End Views to aid in diagnosis.

Conditions for Running the DTC
    • The engine run time is greater than 5 seconds.
    • The 1-2 SS is command on.

Conditions for Setting the DTC

DTC P0973 sets when either of the following conditions occurs for 4.3 seconds:

    • The TCM detects an open in the 1-2 shift solenoid valve circuit when the 1-2 SS is commanded on.
    • The TCM detects a short to ground in the 1-2 shift solenoid valve circuit when the 1-2 SS is commanded on.

Action Taken When the DTC Sets
    • The TCM requests the ECM to illuminate the check powertrain icon during the second consecutive drive trip in which the conditions for setting the DTC are met.
    • The TCC commands maximum line pressure.
    • The TCM inhibits 3-2 shift if vehicle speed is less than 40 km/h.
    • The TCM freezes transmission adaptive functions.
    • At the time of the first failure, the TCM records the operating conditions when the conditions for setting the DTC are met. The TCM stores this information as a Failure Record.
    • At the time of the second failure, the ECM records the operating conditions when the conditions for setting the DTC are met. The ECM stores this information as a Freeze Frame.
    • The TCM stores DTC P0973 in TCM history.

Conditions for Clearing the DTC
    • The ECM turns off the check powertrain icon after the fourth consecutive drive trip in which the TCM does not send a check powertrain icon illumination request.
    • Tech 2 can clear the 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 following numbers refer to the step numbers in the diagnostic table:

4 Checks the ability of the TCM to control the solenoid.

5 Checks for supply voltage to the 1-2 SS valve.

6 Checks the ability of the TCM and wiring to control the ground circuit.

8 Checks the resistance of the control valve body wiring harness and the 1-2 SS valve.

9 Checks if the 1-2 SS or control valve body wiring harness is shorted to the transmission housing.

13 Checks if the control valve body wiring harness is shorted to ground.

14 Checks if any of the other solenoids in the transmission are shorted to ground.

Step

Action

Yes

No

1

Has the Diagnostic System Check been performed?

Go to Step 2

Refer to Diagnostic System Check - Automatic Transmission

2
  1. Connect Tech 2 to the DLC.
  2. Turn on the ignition, with the engine off.

    3. Important: Before clearing the DTC, use the Tech 2 Freeze Frame/Failure Record in order to record the transmission parameters at the time the DTC set. Using Tech 2 to clear the DTC(s) erases the Freeze Frame/Failure Record records from the TCM.

  3. On Tech 2 select: Transmission/Automatic Transmission/Diagnostic Trouble Codes/Freeze Frame.
  4. Select the relevant DTC and note the parameters at the time of the DTC setting.
  5. On Tech 2 select: Diagnostic Trouble Codes/Clear Engine and Transmission DTCs.
  6. Follow the instructions on Tech 2 and clear the DTCs.

Are any of the following DTCs also set?

    • P0787
    • P0976
    • P2764
    • P2769

Go to Step 3

Go to Step 4

3

Inspect fuse F8 and check if it is blown, refer to Section 120 Fuses, Relays and Wiring Harnesses.

Is the fuse blown?

Replace the fuse Go to Step 12

Go to Step 5

4
  1. On Tech 2 select: Transmission/Automatic Transmission/Miscellaneous Tests/Shift Solenoid A.
  2. With Tech 2 command the shift solenoid A ON and OFF.
  3. On Tech 2 select: Data Display/1-2 Shift Data.

Does Tech 2 display the Shift Solenoid A Circuit as Okay?

Check for an intermittent fault in the circuit, refer to Testing for Intermittent Conditions and Poor Connections

Go to Step 5

5
  1. Turn off the ignition.
  2. Disconnect connector X121 -- X1 from the transmission.

    3. Important: Additional DTCs may set.

  3. Install Tool No. J 44152 Jumper Harness (20 pins) on to the harness connector X121-X1.
  4. Turn on the ignition, with the engine off.
  5. Using a test lamp, probe between connector X121-X1 pin E and a known ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 15

6
  1. Using a test lamp, probe connector X121-X1 pin E with the ground lead to connector X121-X1 pin A.
  2. On Tech 2 select: Automatic Transmission/Miscellaneous Tests/Shift Solenoid A.
  3. With Tech 2 command the shift solenoid A On and Off three times.

Does the test lamp turn on and off with each command?

Go to Step 8

Go to Step 7

7

Is the test lamp always illuminated?

Go to Step 16

Go to Step 17

8
  1. Remove Tool No. J 44152 from the harness connector X121-X1 and install on to the transmission connector X121-X1.
  2. Using a multimeter set to measure resistance, probe across transmission connector X121-X1 pins E and A.

Does the multimeter display 19-31 Ω?

Go to Step 9

Go to Step 10

9

Using a multimeter set to measure resistance, probe between:

    • Transmission connector X121-X1 pin E and a known ground.
    • Transmission connector X121-X1 pin A and a known ground.

Does the multimeter display greater than 250 kΩ in both instances?

Check for an intermittent fault in the circuit, refer to Testing for Intermittent Conditions and Poor Connections

Go to Step 11

10
  1. Remove Tool No. J 44152 from the transmission.
  2. Gain access to the 1-2 SS and the control valve body wiring harness, refer to Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness.
  3. Disconnect the internal connector from the 1-2 SS.
  4. Using a multimeter set to measure resistance, probe across the 1-2 SS pins.

Does the multimeter display 19-31 Ω?

Replace the control valve body wiring harness, refer to Control Valve Body and Wiring Harness Removal Go to Step 19

Replace the 1-2 SS, refer to Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness Go to Step 19

11
  1. Remove Tool No. J 44152 from the transmission.
  2. Gain access to the 1-2 SS and the control valve body wiring harness, refer to Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness.
  3. Using a multimeter set to measure resistance, probe between each of the 1-2 SS pins and a known ground.

Does the multimeter display 250 kΩ in both instances?

Replace the control valve body wiring harness, refer to Control Valve Body and Wiring Harness Removal Go to Step 19

Replace the 1-2 SS, refer to Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness Go to Step 19

12

Test circuit 339 for a short to ground connector X121-X1 pin E and the splice.

Did you find and correct the condition?

Go to Step 19

Go to Step 13

13
  1. Gain access to the control valve body wiring harness, refer to Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness.
  2. Test for a shirt to ground in the control valve body wiring harness.

Did you find a short to ground condition?

Replace the control valve body wiring harness, refer to Control Valve Body and Wiring Harness Removal Go to Step 19

Go to Step 14

14
  1. Test each solenoid for a short to ground.
  2. Replace the faulty solenoid as necessary.

Did you complete the replacement?

Go to Step 19

--

15

Test circuit 339 for an open circuit between connector X121-X1 pin E and the splice.

Did you find and correct the condition?

Go to Step 19

--

16

Using a multimeter, test circuit 1222 for a short to ground.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

17

Using a multimeter, test circuit 1222 for an open circuit.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

18

Replace the TCM, refer to Transmission Control Module Replacement.

Did you complete the replacement?

Go to Step 19

--

19

Perform the following procedure in order to verify the repair:

  1. On tech 2 select: Diagnostic trouble Codes/Clear Engine and Transmission DTCs.
  2. Follow the instructions on Tech 2 and clear any DTCs.
  3. On Tech 2 select: Data Display/1-2 Shift Data.
  4. Drive the vehicle in D4 and ensure the following conditions are met:
    5. • The TCM commands the Shift Solenoid A On and the Shift Solenoid A Circuit status parameter displays Okay.
    • The TCM commands the Shift Solenoid A Off and the Shift Solenoid A Circuit statue parameters displays Okay.
    • All conditions are met for 5 seconds.
    • 5 On Tech 2 select:
    • Diagnostic Trouble Codes/Read DTC Information.

Has DTC P0973 set?

Go to Step 2

Go to Step 20

20

On Tech 2 select: Diagnostic Trouble Codes/Read DTC Information.

Does Tech 2 display any DTCs you have not diagnosed?

Refer to Scan Tool Data List

System OK

When all diagnosis and repairs are completed, check the system for correct operation.