|
|
Post by teixeluis on Jul 17, 2018 21:28:37 GMT
Hello,
I have a VW Polo 6C TDI (2014 facelift) featuring a BCM with the folowing characteristics:
Control unit: 09 Central Electrics
System description: BCM PQ26 Hi4R
Software number: 6C0937089A
Software version: 0047
Hardware number: 6C0937089
Hardware version: H06
ODX name: EV_BCMA0
ODX version: 004003
Long coding:
000008404253005B4F844000400703880000580251010000000000000000
Subsystems:
Subsystem: J386__TSG_FT
Long coding: 0400A0
Subsystem: J387__TSG_BT
Long coding: 1400A0
Subsystem: J388__TSG_HL
Long coding: 0400A0
Subsystem: J389__TSG_HR
Long coding: 1400A0
I have replaced the original incandescent trunk light bulb with an LED, but it turns on somewhat erratically, sometimes dimming as if it would be poor contact when it is not.
Does anyone knows if this BCM defines any adaptation in its long coding so that it can better adjust for an LED as a load, instead of the original bulb (leuchte channel settings)?
I suspect the behaviour relates to the bulb testing performed by the BCM. As in this case the load is very low, it probably enters some kind of cold testing and cutoff loop.
Curiously for the interior lights (which I have also replaced by LEDs) no such problem occurs, as these work fine and dim just like the original bulbs. In both cases I have desoldered the dummy load resistors that these LEDs come with.
Thanks in advance.
Cheers,
Luis Teixeira
|
|
|
|
Post by teixeluis on Sept 8, 2018 19:40:00 GMT
Just an update on this topic:
- have experimented with the "Leuchte30 INNENLICHT A68" (in the 09 BCM module) adaptation by changing "Type_Of_Load_30" from "allgemeineGluehlampe12W" to "LED Kleinleistung ohne Open Load Diagnose" but no change in the behaviour: the same flickering most of the time, while at times the light settles and runs continuously;
- have replaced the light with a more powerful LED (it consumed about 30 mA, while the new one consumes around 80-100 mA), but the result is the same
Even though from the list of available adaptations this is the one which seems to relate to the trunk / boot lighting, gien the result I am not entirely convinced. Also, the remaining interiror lights are not affected, and are also LEDs with the load resistor removed.
Anyone has a table with the exact meaning of each leuchte (lamp) entry? Based on notes from other people that have experimented with these leuchte settings, each entry establishes the mapping between the physical lamp and the logical function in the car (e.g. left turn signal, brake lights, low beam, high beam, etc). This being the case, it creates a large degree of flexibility for the manufacturer.
Also there is another detail worth mentioning: running output tests for interior lights does not take effect on the trunk light. Also the output test for the trunk light does not produce any result. This suggests that the interior light channel and the trunk light are separate. The remaining doubt is where is the trunk light mapped, if it is at all mapped in the BCM.
Is it possible that this BCM may not yet have all of the adaptations correctly and/or fully indentified and labelled?
Luis Teixeira
|
|
|
|
Post by teixeluis on Sept 9, 2018 13:24:17 GMT
A few more findings, after a bit of thinking and reaching the assumption that it would not make sense that the luggage compartment light would be in the same function as the interior lights: i.e. the trunk door can be opened separately, with only the trunk light being needed. As such I went through the output tests to try to understand what channel was switching the trunk light.  Unlike what the label suggests, the "Luggage compartment light" adaptation has no effect. Eventually corresponds to some other pin of the BCM which is not used in this vehicle (maybe a good idea to fix this in Obdeleven). Going through the channels and available output tests, the closest thing I imagined it could be related to the trunk light would be some generic output using clamp 30g (devices that are switched directly from the battery, without requiring the ignition key to be on. As such there is an output test for Clamp 30G. Tried to run it, and yes, it would turn off the trunk light if the trunk door would be open. With the trunk closed this test has no effect (the mechanical switch appears to take precedence over the switching on the BCM), i.e. it is not able to turn on the light. The test has to be run without time limit, otherwise it fails. After the output test, I attempted to change the "Leuchte" adaptation that appeared (by the label) to best corresponded to this function. Tried to change the load type on the "Leuchte29 LK39G A69". Changed from "allgemeineGluehlampe12W" to "LED Kleinistung ohne Open Load Diagnose":  The change was done with success, but again there was no apparent change in behavior. When the trunk door is opened for the first time the light flickers for some time, until it finally holds stable. Opening the door again (after a short time), causes the light to turn on normally. Running an output test afterwars seems to turn the light on and off normally. It seems as if the BCM runs the open load test (probably a sequence of small pulses of current, before staying on) only once in a while. If I was indeed playing with the correct adaptation, then there is the likelihood that it doesn't change the load verification loop, only the effect of the detection, for DTC purposes (just a guess). In the load type list, there are aliases for apparently the same thing, as is the case for "LED Kleinistung ohne Open Load Diagnose" and "LEDKleinleistungohneOpenLoadDiagnose". Also attempted to change between the two, but with no change in the behavior:  Regarding this BCM adaptations in general, there are two apparently duplicate sections: "Lighting configuration" (or similarly named entry), and the individual Leuchte entries with its group of configurations. The parameters that are accessible are the same, with the difference that "Lighting configuration" has the bulk of all the leuchte adaptations, which is harder to navigate. Being the case that it is the same, it could potentially be interesting clutter to remove. Thank you Best regards, Luis Teixeira |
|
|
|
Post by teixeluis on Sept 11, 2018 22:14:20 GMT
Just to update again on this, the last few times I opened the trunk, the light haven't been flickering anymore. Assuming physical conditions are more or less the same, I wonder if the adaptation could have taken some time to take effect. Did anyone had a similar experience with other lights related adaptations?
|
|
|
|
Post by teixeluis on Oct 25, 2018 22:18:21 GMT
After some time with the adaptations to avoid the flickering of the trunk light, I believe I kinda relieved the problem by changing the light dimming (Dimming_AB_29) from the default 100, to 127. Playing with the full range of values of this parameter, effectively dims the light from totally off to full on. It still flickers once in a while, at random intervals, but only happens 10-20 % of the time. Also, changing Light_Function_A_29 from "Klemme 30G" to "aktiv 100%" seemed to have improved slightly as well. Anyway, it still flickers enough that it is not a result to call home about. It is somewhat weird that the BCM has a different behaviour in respect to this light in particular, whereas with the interior lights, which I have replaced with leds from which I have desoldered the resistor (the so called "CAN BUS" lamps -  the wildest non-sense that became widespread in the auto industry in my oppinion), it works perfectly normal. It is for sure related to some load detection loop. And apparently is totally inaffected by the Type_Of_Load adaptation, which seems to indicate that the later serves only for potentially raising PID's. Given the range of tweaks I did so far, I suppose it is unlikely that a complete fix is possible just by changing some adaptation. I guess I will have to put a "CAN BUS resistor" instead and hope the car doesn't catch fire. Luis Teixeira |
|
the wildest non-sense that became widespread in the auto industry in my oppinion), it works perfectly normal.