P0733

ALLISON AUTOMATIC TRANSMISSION

DTC P0733





Circuit Description for Allison Automatic Transmission
The Transmission Control Module (TCM) uses input from the input speed sensor and output speed sensor to determine gear ratios. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.
DTC P0733 is a type A DTC.

Conditions for Running the DTC
^ The components are powered and ignition voltage is greater than 9 V and less than 18 V.
^ Output speed exceeds 200 RPM.
^ Third range is selected and attained.
^ DTCs P0716, P0717, P0721, P0722, P0726, and P0727 are not active.

Conditions for Setting the DTC
DTC P0733 sets when the calculated third range ratio, steady state, differs from the known third range ratio.

Action Taken When the DTC Sets
^ Fails to 4th range while diagnostic response is active.
^ If the shift selector is moved to NEUTRAL, then the transmission will shift to NEUTRAL.
^ If the shift selector is moved to REVERSE, then the transmission will shift to NEUTRAL.
^ If the shift selector is returned to a forward range and the transmission is compromised by overspending or direction change, then the transmission will lock in NEUTRAL.
^ DTC P0733 will be stored in the TCM history.
^ The TCM freezes shift adapts (DNA).
^ Illuminates the MIL when active.
^ TCM inhibits TCC engagement.

Conditions for Clearing the MIL/DTC
A scan tool can clear the code from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

Diagnostic Aids
^ Incorrect TCM calibration will cause this DTC to set.
^ Incorrect ratio codes typically indicate mechanical conditions with specific clutches, i.e. C1 and C3 for 3rd range.
^ Incorrect ratio code could indicate hydraulically failed solenoid. Check DTC information for specific solenoid.
^ You may have to drive the vehicle to experience fault. Clutch test mode can be used to check stall speed.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This step tests ignition voltage.
4. This step tests speed sensor readings.
5. This step tests for turbine speed not remaining at zero in third range.
6. This step checks for evidence of clutch failure.