In this entry, I will gather all the information, which corresponds to the adaptations of the automatic transmissions.
In the beginning – basic information.
The aim of the adaptations – ensure that the switching of the gears is maximally even.
Groups of the adaptations of the transmission:
- pressure adaptations of friction disc control solenoids;
- time adaptations of friction disc control solenoids;
- other adaptations (management of torque converter, etc.)
The first adaptations of the transmission are created after assembly of the car, performing the pre-sale test drives in the manufacturer’s polygon. The adaptations of the transmission continue to regenerate all lifetime of the transmission if a range of conditions is fulfilled:
- there are no problems with the technical condition of the transmission itself (indications – error message regarding some hub);
- the engine of the car works in full functionality mode;
- there are no error messages in modules, related to the performance of the transmission (for example: regarding ASC/DTC, trailer module, etc.).
What are the consequences if the transmission does not regenerate the adaptations automatically for some reason?
The performance of the transmission slowly (in weeks, months) becomes more and more incorrect. The jerks and slow-downs in switching will appear – it is unavoidable. The elements of the transmission wear out, their parameters change, the adaptations should follow the changes. The “specialists” may offer the repair or the replacement of the transmission as the only viable solution.
Besides, I would like to pay special attention, especially to the part of the full functionality mode of the engine. Full functionality mode is reached, if:
- there are no error messages regarding the performance of the engine;
- the software of the engine is not modified;
- after each repair of the engine (which was justified and necessary), the correct re-adaptation of the engine is performed.
Most notable in the second point:
- deleted (cleared) error message map (so – actually the error messages are recorded in the DDE/DME error message memory, but they don’t appear in the error message list anymore), or;
- after changes in the management maps, the engine management is not able to calculate the energetical model.
Very shortly about the second situation. The management systems of BMW (both DDE and DME) of the last 10+ years work by the principle of the energetical model. It means – the virtual model of the engine is included in the engine management system, it is used to check the conformity of all data of the system (and their functionality). If the management maps are modified, with a probability of 99% the energetical model calculated by DDE/DME, will not correspond to the included formulas. DDE/DME will desperately search for the “damaged” hub, performing continuous service functions (checking of the peripherals and measuring of their parameters), but – it will not be possible to find the culprit.
So – if the software of your car is modified (typically for diesel engines: eliminated flaps in the inlet manifold; removed EGR or even DPF. For the petrol engines – switched off control probes behind the CO catalytic converters, for all engines – increased power), with a probability of 99%: the transmission WILL NOT create correct adaptations. Unfortunately, this is one of the side effects, which have to be taken into account in case of any modifications of DDE/DME.
Readaptation of the transmission has to be done:
- after its repair;
- after its service maintenance (replacement of oil, filter);
- if the transmission was not able to regenerate the adaptations for a longer time (for example, the engine has had performance problems or it was not running in the full functionality mode);
- the performance of the transmission is not smooth.
Note: The re-adaptation of the transmission is NOT (just) deleting the adaptations. Re-adaptation has to be done, strictly following the required procedure (defined by its manufacturer) for each model of the transmission!
What are the counterarguments for the re-adaptation of the transmission?
- After the re-adaptation, things will become even worse. Such problems can appear if there is a defect of the transmission (it has to be repaired), of the adaptation procedure, is not followed. Or there are other problems as if not directly related to the transmission (already mentioned problems of full functionality of the engine, etc.);
- after the attempt of the re-adaptation, the error messages regarding the performance of the transmission will appear. Cause: the “corridor” of initial adaptations is more narrow than the complete (initial + wear) corridor of the adaptations. Yes, it can happen (it depends on the model of the transmission and the software release), but you have to understand – if the transmission is so worn out, that its adaptations “drop” out the allowed corridor – it has to be repaired! Postponing the problems will not help!
Here’s a note: many “upgraders” of the software do not suggest to perform the re-adaptation of the transmission. Not after the service maintenance, not in case of the average performance of the transmission. The reason is simple: as the engine does not work as it should (after the “upgrade” of the software), very often the re-adaptation of the transmission ends with an unsatisfactory result (sometimes the transmission even is not able to create new adaptation).
Note: the manufacturer of the transmission defines the interval when the oil filter and oil itself should be replaced. Exact data you will find in the Service manual of the exact model, but indicative values:
- 80.000 .. 160.000km; or
- 6 .. 10 years.
Don’t listen if somebody tells you that the oil and oil filter of the transmission should not be replaced! Lifetime is not 300.000km and 20 years! Follow the data of the Service manual!
Example.
Vehicle: E60. Performance of the transmission – unsatisfactory. Switching is very uneven – with jerks; the car shivers, driving is very uncomfortable. The user of the car has already created a habit – at the moment when the gearbox could switch to the next gear, he remits the accelerator pedal for the switching to happen a little bit more smoothly and at an “expected” moment.
Why has such a situation developed?
For a long time, the engine (N53B25) has worked in limited functionality mode (actually – in emergency mode). Its NOx system was not repaired, but simply “switched” off. The error message map – “thinned”. Accordingly – the renewing of the transmission adaptations was paralyzed.
After repair of the engine (restoring full functionality mode and re-adapting), the re-adaptation of the transmission was done.
I call your attention to the adaptation data before and after re-adapting the transmission.
Before:
After:
Here, a simple table with data before/after:
I believe, you see the massive difference in the pressure adaptations of valves A, C, and E? Even more: before re-adaptation, the adaptations of the C valve were far from 0, after – almost perfect. The situation of E valve is ever harsher – the “direction” of the adaptations: opposite! Also, the differences in time adaptations (although the numbers are smaller in an absolute size; the max allowed values are much lower) before/after are not less dramatic! I believe, even the most abundant skeptics will have nothing to object – it is clear that the transmission has not regenerated the adaptations. Although there were no error messages regarding the transmission itself not now, not in the past.
After the re-adaptation, the performance of the transmission changed radically! The switching became smooth – precisely as it should be!
