Diagnostic Test

VISUAL INSPECTION
NOTE:
Make certain that the vehicle is not towing loads weighing more than the recommended towing capacity.
1. Check Transmission Cooler for airflow restrictions and internal fluid restrictions.
2. Check Transmission fluid level and if low, check for leaks.
3. Check Transmission Cooler lines for restrictions.
4. Check Transmission case vent for restrictions.
  Were any problems found?
  
  Yes
  - Repair in accordance with the Service Information.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .
  No
  - Go To 2
CHECK FOR OTHER TRANSMISSION DTCS
1. With the scan tool, read Transmission Control Module (TCM) DTCs and record on the repair order.
  Are there any other TCM DTCs?
  
  Yes
  - Repair the other TCM DTCs. Refer to 948TE/9HP48 AUTOMATIC TRANSMISSION - DIAGNOSTIC CODE INDEX .
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .
  No
  - Go To 3
CHECK TRANSMISSION TEMPERATURE SENSOR CIRCUITS FOR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the TCM harness connector.
3. Remove the Transmission side cover in accordance with the Service Information and disconnect the Transmission Temperature Sensor harness connector.
4. Connect a jumper wire between the (T819) Transmission Temperature Signal circuit and the (T23) Sensor Ground circuit at the Transmission Temperature Sensor harness connector.
5. Measure resistance between (T819) Transmission Temperature Signal circuit and the (T23) Sensor Ground circuit at the TCM harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Replace the Transmission Fluid Temperature Sensor in accordance with the Service Information.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .
  No
  - Repair the (T819) Transmission Temperature Signal circuit or the (T23) Sensor Ground circuit for an open or high resistance.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .