For a complete wiring diagram Refer to Section 8W
The Transmission Control Module (TCM) constantly calculates the transmission ratio based on the input speed sensor 1 and 2 (N2-N3) signals and the calculated output shaft speed. The intent of this diagnostic is to detect if the transmission is trying to mechanically shift into a different gear than the TCM intends.
NOTE: The transmission control module is programmed to immediately place the transmission into neutral if P0730 or P1731 codes are set. These codes indicate that the transmission experienced an unknown or incorrect gear ratio. Placing the transmission in neutral prevents potential catastrophic failure. When this occurs, the transmission will remain in neutral until the vehicle slows to 29 Km/h (18 mph).
Engine rpm greater than 450 rpm, no N2 - N3 input speed sensor errors present, no gear selector lever errors present, no ABS system errors, and vehicle speed above 10 Km/h (6 mph).
No shifting operation and actual gear differs from the target gear. No shifting operation - actual (calculated) gear differs from the target (expected) gear, no plausible gear is calculated, actual (calculated) turbine speed is greater than 300 rpm or calculated transmission ratio is above threshold. During an Upshift - actual (calculated) gear is less than target (expected) gear. During Downshift - actual (calculated) gear is greater than target (expected) gear.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Are there any ABS DTCs present?
Are there any transmission solenoid, speed sensor and/or any other transmission electrical related DTCs present?
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.
Is the fluid level and condition correct?
Did the environmental data show the code setting during a 3-4 upshift or 4-3 downshift?
NOTE: Debris may enter through the vents in the top of the valvebody. 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.
Were there any problems found?