46 3-4 Shift Abort

THEORY OF OPERATION:
The table illustrated below shows the clutches which are applied in each gear:





When shifting from 3rd to 4th gear, the turbine speed may increase instead of decrease. This would indicate a problem in the UD, OD, or 2-4 hydraulic circuit. When this is detected, the 3-4 shift is aborted temporarily. The TCM attempts the 3-4 shift again. After three unsuccessful attempts, the trouble code is set.

If turbine speed runs away during a 3-4 shift (heads for 2nd gear ratio instead of 4th gear ratio), a 3-4 failure condition will occur. If three failure conditions are recorded in a given key start, the code will be set.

LIMP-IN:
NO

WHEN MONITORED/SET CONDITIONS:
During the 3-4 shift.

TRANSMISSION EFFECTS:
All model year and calibrations. 4th gear is inhibited during the key start in which the code is set. Will attempt 3-4 shift again during next key start. The transmission will not go into limp-in mode

POSSIBLE CAUSES:
- Internal transmission failure when accompanied by a speed ratio fault
- If code 46 is present by itself and not repeatable during a road test, it can be ignored. This can be set by repeated lift foot 3-4 upshifts followed by 4-3 kick-downs if they are performed close together