Circuit/System Testing

Engine ON, apply the parking brake, 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, test or replace the Transmission Input Speed Sensor (ISS). Refer to the INPUT SPEED SENSOR REPLACEMENT procedure.
Operate the vehicle in 3rd gear. Observe Gear Ratio parameter on the scan tool. The Gear Ratio parameter should not equal 2.84:1.
- If the Gear Ratio parameter equals 2.84:1 while in 3rd gear, test or replace the:
- 3-4, 4-5 shift solenoid valve assembly
- U1 shift valve
  Refer to the CONTROL VALVE BODY ASSEMBLY DISASSEMBLE procedure.
  - If all conditions test normal, test or replace the control valve body assembly. Refer to CONTROL VALVE BODY REPLACEMENT procedure.
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 Torque converter assembly, Input shaft, and Fluid pump stator shaft assembly. Refer to TORQUE CONVERTER ASSEMBLY REMOVAL , FORWARD AND DIRECT CLUTCH ASSEMBLY ASSEMBLE and FLUID PUMP CLEANING AND INSPECTION procedures.
- If all conditions test normal, test or replace the transmission.
Inspect the control valve body assembly for the following conditions. The conditions should not be found.
- Stuck lock up relay valve
- Stuck lock up control valve
- Stuck TCC check valve
- Stuck secondary regulator valve
- Stuck solenoid relay valve
- Stuck TCC lock up PC solenoid valve assembly
  Refer to CONTROL VALVE REAR BODY DISASSEMBLE and MIDDLE CONTROL VALVE BODY DISASSEMBLE .
  - 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.