Circuit/System Testing

WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.

Observe the scan tool Transmission OSS parameter while driving the vehicle. The reading should correspond to a known properly functioning OSS.
- If the OSS is malfunctioning, replace the Transmission Output Speed Sensor (OSS). refer to the Output Speed Sensor Replacement procedure.
Stop the vehicle, apply the parking brake, engine at idle, select P (park) using the Shift Control.
Observe the scan tool Transmission ISS parameter. The reading should be within 400-800 RPM.
- If the ISS parameter is not within the specified range, replace the Transmission Input Speed Sensor (ISS). Refer to the Input Speed Sensor Replacement procedure.
Firmly apply the brake, select D (drive) using the Shift Control.
Observe the scan tool TCC Slip Speed. The reading should be within 0-100 RPM.
- If the TCC Slip Speed is not within the specified range:
  - Ignition ON, engine OFF, command shift solenoid 1 ON and OFF with a scan tool. The solenoid should click when commanded ON.
    - If the solenoid does not click, replace the 1st shift solenoid valve assembly. Refer to Control Valve Body Assembly Disassemble .
  - Command shift solenoid 3 ON and OFF with a scan tool. The solenoid should click when commanded ON.
    - If the solenoid does not click, replace the 1-2, 2-3, reverse shift solenoid valve assembly. Refer to Control Valve Body Assembly Disassemble .
  - Perform a line pressure test. Refer to Line Pressure Check procedure.
  - Remove the control valve body cover. Refer to Control Valve Body Cover Removal procedure.
  - Inspect the inside of the control valve body cover for excessive sediment. There should not be excessive sediment.
    - If excessive sediment is found inspect and replace as necessary the second coast clutch, second clutch, forward clutch, and 1-2 reverse clutch. Refer to Transmission Fluid Pump Cleaning and Inspection , 2nd Clutch Assemble , Forward and Direct Clutch Assembly Assemble , and 1-2-Reverse Clutch Plate Assemble procedures.
  - Inspect the control valve body assembly for the following conditions. The conditions should not be found.
    - Stuck U1 shift valve
    - Stuck M1 shift valve
    - Stuck U2 shift valve
    - Stuck shift pressure relay valve
    - Stuck neutral relay valve
    - Stuck line pressure control solenoid valve assembly
      refer to Control Valve Rear Body Disassemble and Control Valve Body Disassemble - Middle .
      - If any of the above conditions are found, replace the valve body assembly. Refer to Control Valve Body Replacement procedure.
  - Verify that the control valve body has been serviced within the past 3 months.
    - If the control valve body has not been serviced, replace the control valve body assembly. Refer to Control Valve Body Replacement procedure.
  - If all circuits and components test normal, replace the transmission.
If all circuits and components test normal, replace the transmission.