125000477 - C14 THE GEARS DO NOT ENGAGE

It skips a gear/the requested gear is not engaged.
If no errors are detected, the problem could be due to incorrect use of the vehicle by the customer.
Results of the tests
0OIL LEVEL CHECKAll OKProblems metOperation
Check the oil level as described in See Test    See Test 2127B OIL LEVEL CHECKContinue to Step 2Level below the Max referenceTop up the oil levelContinue to Step 1
Level above the Max referenceReduce to the Max levelContinue to Step 2
1CHECK FOR OIL LEAKSAll OKProblems metOperation
Check that there are no oil leaks as described in See Test    See Test 2127C HYDRAULIC GEAR SELECTION SYSTEMContinue to Step 2Oil leaks detectedReplace/repair the parts concerned, and top up the oil levelContinue to Step 1

Check that there are no control unit errors. In particular:

  • Engagement sensor error
  • Selection sensor error
Continue to Step 4Presence of one or more of the errors included in the listContinue to Step 1
Check the faults according to the See Test    See Test 2127I What to do for error in Selespeed control unitContinue to Step 2Faulty connectionsRepair/replace the wiringContinue to Step 2
2SENSOR REPLACEMENTAll OKProblems metOperation
If there is a gear engagement sensor error and no faults are detected at the connections/wiring, replace it Op. 2127E42and check that the position reading is correct by carrying out a series of C.M.
It is advisable to fit tool n° 1870753001 before removing the potentiometer from the hydraulic unit
If there is a gear selector sensor error and no faults are detected at the connections/wiring, replace it Op. 2127E40and check that the position reading is correct by carrying out a series of C.M.
Continue to Step 3.
3AFTER THE CHECKS ON THE FAULTS DETECTEDAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisThe fault persistsContinue to Step 4
4PARAMETERS CHECK USING THE EXAMINERAll OKProblems metOperation
Check that the failed engagements counters in the parameters environment (failed engagement counters for: neutral, 1st-5th and reverse) are all at zero.Continue to Step 7These counters are at a value different from zeroMake a note of/print out the screen showing the failed engagement counters.Continue to Step 5
5SELF CALIBRATIONAll OKProblems metOperation
With the Examiner Plus or Smart, in active diagnosis start end-of-line/Service self-calibrationContinue to Step 6The self-calibration is not successfulContinue according to the instructions for the diagnostic equipment
6ROAD TESTAll OKProblems metOperation
Carry out a road test, making sure to make as many gear changes as possible with all the available gears (under different engine speed and load conditions).

Check the failed engagement counters in the parameters environment (failed engagement counters in: neutral, 1st-5th and Reverse).

  • Print out/make a note of the new counter values. Compare the new values of the parameters with those noted down previously, checking that there is not a signficant increase for one or several counters
End of diagnosisThere is a significant increase for one or more countersContinue to Step 7
7SLOW FINGER CHECKAll OKProblems metOperation
Using the Examiner Plus or Smart in active diagnosis, launch the procedure for checking the slow fingerContinue to Step 8The finger is slowReplace the finger fixing boltContinue to Step 8
8THE FAULT PERSISTSAll OKProblems metOperation

The fault may be caused by false contacts on the gear lever: check the state of the connections and wiring for the lever.

  • In any event, contact Technical Service for further information on the problem.
End of diagnosis.