Diagnostic Test

CHECK IF ABS DTCS ARE PRESENT
1. With the scan tool, check for ABS DTCs.
  Are there any ABS DTCs present?
  
  Yes
  - Refer to DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Diagnosis and Testing and perform the appropriate symptom(s).
  No
  - Go to step 2
CHECK IF TRANSMISSION SOLENOID DTCS ARE PRESENT
1. With the scan tool, check for other transmission DTCs.
  Are there any transmission solenoid, speed sensor and/or any other transmission electrical related DTCs present?
  
  Yes
  - Refer to the symptom list and perform the appropriate symptom(s).
  No
  - Go to step 3
CHECK TRANSMISSION FLUID LEVEL
NOTE: Low fluid level can be the cause of many transmission problems. Visually inspect the transmission and cooler lines for leakage and repair as necessary and adjust the fluid level per the Service Information. If no visual leaks are observed and the vehicle has obtained over 1610 km (1000 miles) from either new or transmission service, a fluid level check is unnecessary.
1. Check the transmission fluid level and condition in accordance to the Service Information.
  Is the fluid level correct?
  
  Yes
  - Go to step 4
  No
  - Correct the fluid level in accordance to the Service Information.
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure
CHECK ENVIRONMENTAL DATA
1. With the scan tool, check environmental data for P1731.
  Did the environmental data show the code setting during a 3-4 upshift or 4-3 downshift?
  
  Yes
  
  NOTE: Debris may enter through the vents in the top of the valve body. The debris can be a very small sliver that is visibly unnoticable unless flushing onto a fine filter paper. The debris has the potential to stick the 3-4 Shift Pressure or 3-4 Holding valves. If either valve is stuck during a 3-4 upshift or 4-3 downshift, a shift flare, bump shift, harsh shift, or neutraling out will occur.
  - Flush and clean the Valve Body in accordance to the Service Information. Pay particular attention to the 3-4 shift pressure and 3-4 holding valve.
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure
  No
  - Go to step 5
CHECK FOR INTERNAL TRANSMISSION PROBLEM
1. Check for an internal Transmission mechanical problem(s).
2. Remove the Transmission Oil Pan and inspect for excessive debris or a plugged Transmission Oil Filter in accordance to the Service Information.
3. Inspect the valve body for foreign material, starting with the four valves associated with the shift described in the environmental data (shift pressure, holding, overlap, command), and continue on to the other valves.
4. This DTC is usually set due to an internal transmission problem such as but not limited to: stuck solenoid valve and/or contamination in the valve body, broken springs, leaking clutch seals, dislodged or broken snap ring etc.
5. Check the Service Information for the appropriate service procedure(s) and any other possible causes.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure
  No
  - Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCM in accordance to the Service Information.
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure