Control Solenoid Valve and Transmission Control Module Assembly Output Shaft Speed Input Test: Notes

Special Tools 

EL 38522  Variable Signal Generator

Fig 1: Transmission Control Module Assembly Output Shaft Speed Input Testing

Courtesy of GENERAL MOTORS COMPANY

The purpose of this test is to provide a simulated output speed sensor signal to the control solenoid valve assembly Transmission Output Shaft Speed Sensor input circuits in order to verify the control solenoid valve assembly is able to process the output speed sensor signal.

1. Vehicle OFF, remove the control valve body cover. Refer to Control Valve Body Cover Removal .
2. Connect the Q8 control solenoid valve assembly X1 harness connector.
3. Vehicle OFF, disconnect the OSS wiring harness connector X4 (1) from the Q8 control solenoid valve assembly.
4. Vehicle ON, test for 8.3-9.3 volts at terminal A and ground.
   • If not within the specified range 

     Replace the Q8 Control Solenoid Valve Assembly.

   • If within the specified range 
5. Vehicle OFF, using the EL 35616  terminal test kit, connect the EL 38522  variable signal generator red lead to the OSS signal circuit terminal B on the TCM.
6. Connect the black lead from the EL 38522  variable signal generator to ground.
7. Set the EL 38522  variable signal generator to 8 volts, the frequency to 120 Hz, and the percent duty cycle to 50 or the normal position.
8. Vehicle ON, verify with a scan tool the Transmission OSS parameter is between 375-400 RPM.
   • If not within the specified range 

     Replace the Q8 Control Solenoid Valve Assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement .

   • If within the specified range 
9. Test the output speed sensor harness for an open, short to ground or short to voltage.
   • If output speed sensor harness is shorted or open 

     Repair or replace harness.

   • If all circuits test normal 
10. Test or replace the B14A Transmission Output Shaft Speed Sensor.