Cause 1: A synchronizer ring in the gearbox is broken.
Diagnosis 1: This case can only be confirmed after disassembling the gear unit.
Solution 1: Replacement of the synchronizer ring.
Diagnosis 1: This case can only be confirmed after disassembling the gear unit.
Solution 1: Replacement of the synchronizer ring.
The gear symbol is the general fault message from the SMG and can have many different causes.
1. hydraulic pressure in accumulator too low
2. clutch cannot be actuated
3. switching / dialling angle sensors deliver implausible values
For further diagnosis, see detailed descriptions of the above problems.
1. hydraulic pressure in accumulator too low
2. clutch cannot be actuated
3. switching / dialling angle sensors deliver implausible values
For further diagnosis, see detailed descriptions of the above problems.
For shifting and clutch operations, the SMG system based on hydraulics requires sufficient pressure in the accumulator. The hydraulic pressure can be displayed as a live measured value in the diagnostic program Inpa or ISTA-D or in other professional testers.
Cause 1: Defective hydraulic pump
Diagnosis 1: The SMG does not build up any hydraulic pressure at all. The pump cannot be heard when the ignition is opened or switched on.
Solution 1: Replace the pump or pump motor. We offer this part in our shop.
cause 2:defective/age-deficient accumulator. The piston accumulator has a nitrogen filling to generate the back pressure, which can gas out with the age of the part.
Diagnosis 2: Observation of the pressure drop in the accumulator in the N-gear without any action. If the hydraulic pressure drops so quickly that the pump has to pump significantly more than once per minute, the accumulator is defective.
Solution 2: Replacing the accumulator. Please note: the accumulator has a limited storage period, which is greatly reduced when stored dry (removed). Therefore it is best to install new parts!
Cause 1: Defective hydraulic pump
Diagnosis 1: The SMG does not build up any hydraulic pressure at all. The pump cannot be heard when the ignition is opened or switched on.
Solution 1: Replace the pump or pump motor. We offer this part in our shop.
cause 2:defective/age-deficient accumulator. The piston accumulator has a nitrogen filling to generate the back pressure, which can gas out with the age of the part.
Diagnosis 2: Observation of the pressure drop in the accumulator in the N-gear without any action. If the hydraulic pressure drops so quickly that the pump has to pump significantly more than once per minute, the accumulator is defective.
Solution 2: Replacing the accumulator. Please note: the accumulator has a limited storage period, which is greatly reduced when stored dry (removed). Therefore it is best to install new parts!
cause 1: leak in hydraulic system
Diagnosis 1: Leaks or leaks result in oil leakage. Therefore, external traces of oil and the continuous loss of hydraulic oil in the expansion tank should be noticed.
Solution 1: Repair the leak by replacing or repairing the components. Leakage often occurs at the clutch actuator (slave cylinder).
Diagnosis 1: Leaks or leaks result in oil leakage. Therefore, external traces of oil and the continuous loss of hydraulic oil in the expansion tank should be noticed.
Solution 1: Repair the leak by replacing or repairing the components. Leakage often occurs at the clutch actuator (slave cylinder).
cause 2:defective / age-deficient accumulator. The piston accumulator has a nitrogen filling to generate the back pressure, which can gas out with the age of the part.
Diagnosis 2: Observation of the pressure drop in the accumulator in the N-gear without any action. If the hydraulic pressure drops so quickly that the pump has to pump significantly more than once per minute, the accumulator is defective.
Solution 2: Replacing the accumulator. Please note: the accumulator has a limited storage period, which is greatly reduced when stored dry (removed). Therefore it is best to install new parts!
Cause 1: Faulty PLDC sensor (clutch position sensor) or cable break
Diagnosis 1: Evaluation of the fault memory
Solution 1: Replace the sensor or repair the cable break.
Diagnosis 1: Evaluation of the fault memory
Solution 1: Replace the sensor or repair the cable break.