Anyway, I advise you not to mess with C1 probes, you'd better put up an independant probe connected to your gauge. If you disturb engine coolant measurement system, this could prevent the fan to startup when temp is over 100°C or to be active all the time!
>> I didn't like the engine telling me it was running at 120 degrees though
So do I !
My new diagnostic toy told me that temperature is rising when the C1 is stopped with its engine idling.
When riding temperature keeps below 90°C... :)
I believe that temperature sensor is a heat variable resistor. So you might put in serie a potentiometer with the probe (outer and middle legs) to allow a trimming of the measurement.
Now the question is "what is the most appropriate value for that pot?"
If I were you I would ohm out the probe after disconnecting it and choose the pot value according to the error ratio of temperature measurement.
- Probe is x omhs
- Real coolant temperature is : y degree
- Measured coolant temperature is z ohms
so % error on measurement is (y-z)/y assuming y>z
so pot should have a value equal or above 2*(x*(y-z)/y)
For this I assume that both pot and probe are linear and that probe needs an ohm up trimming.... Otherwise, probe and pot would have to be put in parallele to lower probe impedance, pot value would be different aswell.
I hope it'll helps and won't startup another horror pictures show in this thread (planes, tanks etc...) :)
Now I've got that information on my new gimmick, without messing with coolant pipes :)
wow, that would be frightening :)
No problem, except if you mind having a bl**dy french accent coming out of this gimmick :)
Ok, did a bit of calculation.
I might be able to propose this device for around 200EUR :
- Electronic board fully tested
- Empty plastic box (board is to be integrated in it)
- BMW diagnostic plug + cord (this one cost almost 20EUR!)
- 9V battery cord + plug (to power the tool when connected to a PC, so it is possible to add/change fault code explanation and update firmware in a near future)
I prefer not integrate the board in the box. why ? Because I don't like doing this :)
That mean that a few holes would have to be done in it and a bit of easy soldering.
Understood, in that case anyone to help me putting up such an initiative ?
I know chinese company able to produce quality PCB for a good price... But I'm affraid that 50 units wouldn't be enough to start an industrial component mounting process...
50 units is way to much regarding my freetime :(
I'll see how much for a single unit and let you know.
Here are the actual features of this tool:
- Read realtime engine parameters : Battery voltage, vehicule speed (more to come: coolant temp, RPM, Load, uptime...)
- Read realtime engine raw parameters : Hex codes strings to be decoded to add more engine parameters...
- Read ECU informations (Software version, factory date, VIN number and chassis number,...)
- Read and decode ECU faults : code, explanation, status (current, stored, nb occurences...)
- Reset current and stored ECU faults
- Read ABS informations (Software version, factory date, ABS serial#,...)
- Read and decode ABS faults : code, explanation, status (current, stored, nb occurences...)
- Reset current and stored ABS faults
You can also read the PDF document attached up there to discover menu navigation (this doc is to be updated).
I hope it's clear :)
The tool easily fit into the right panel box, so I could test real time parameters monitoring while commuting this morning (45km), it works great :)
By the way I added a switch and a buzzer, so I'll be possible to fit it right into the C1 and raise an alarm in case a parameter cross a threshold (coolant temp, fault detection).
Well, not really as this wasn't meant to be done for a commercial purpose. I could built a very limited number of units in case someone ask...
Any advice is appreciated :)
Here is the final version in a box (dim. 90x58x24 mm) :)
Below is attached a quicktour guide of this device.
The C1 use a proprietary BMW plug that is not OBDII, however the management protocol in some aspects is close to ODBII (ISO14230).
I doubt that this display panel would work as C1's ECU does not fully comply with standard protocol for fault codes and engine parameters management. Moreover C1's ECU initialization sequence is very specific. :(
I'm proud to announce that I've reached a rather stable milestone on my C1 diagnostic tool project.
Most of the coding is done and I'm about to borrow prototype unit to a friend for him to fully test any fault code available.
In the meantime you'll find attached a quicktour guide of "C'Mon diagnostic tool".
Here are remaining things to be done:
- make a second prototype to be fitted in a waterproof plastic box.
- decode engine parameters dataset to extract coolant temperature, rpm, engine load, etc...
when I buy my second C1 its alarm was disabled. I asked the guy at BMW Mottorad to reactivate it and he did it for free! (well almost, 1000km service wasn't :) ).
IMHO it should be possible to do the reverse operation aswell. I think you have to unplug the alarm and reconnect a free hanging plug under the dashboard in place. Try to see if a matching plug is present under the dashboard.
Exactly, well guessed !!!:)
And what about designing electronic schematic, PCB prototyping, PCB soldering and its debugging or hacking logical serial signals ?
You might be THE man that I need on the other side of the channel.
btw we could strip off some pictures of this thread that are a bit out of topic :)
A fast update on project :
- I manage to code core functions to navigate through menu using the 4 board buttons (up,left,right,ok)
- Reading ECU identification data and faults works, but yet no translation from numeric to english language (a translation table is to be used, ie Fault 0272 = "Intake Air Temperature Sensor 1 Circuit, Short-circuit to Positive or Open-circuit.")
Here is an overview of current working menu navigation:
<ECU Read Errs>
<ECU Reset Errs>
<ABS Read Errs>
<ABS Reset Errs>
I will be in Germany all next week for professional training purpose, so I should have plenty of free time on afternoon to work on this project :)
More updates to come...
what's the matter with FRENCH stones??? :)
I'm not sure if the abs has is own ECU or if the ECU handle both functions (engine & abs)... In that case it might just be about downloading a new software inside the ECU. I've got some clue on this and could try something later...
No thanks, I manage to buy a working one from an italian ebayer (50EUR) :)
However, if you have the plug that come with the speedo, this would make things easier for me.
Thanks Lawrie, that's a fantastic opportunity to dig deeper into C1's secrets! (don't worry I'll take care of this speedo)
>> so its something built into the speedo itself.
I knew this, when I swapped two ECU, mileage was still the same. The good thing is that ECU must talk to speedo. I wonder how many pins are built into speedo back connector, just to guess what kind of signal might be used...
Do I need to PM you my personnal address or you still have it ? Obviously I'll pay shipping cost ( please use standard flat rate :) )
I would be great if we could get a spare dashboard unit to see what's its guts look like...
That's analogic electronics, IMHO numeric electronics is ways much powerful
Well, that's a simple voltage controlled led decoder that monitor an engine probe output. That could be my B plan if I fail in my investigations :) LOL
I think reprogramming speedo might be possible if the dashboard is connected on same KBUS than ECU, might be my next research playground...
Thanks guys for this cheer up, that's a kind reward for me
Do you remember that one of your jokes started up this project ?
>> Your next task is to develop a diagnostic box that fits on the dash, this little unit must display ANY fault on the C1, & then automaticly fix it. You have 2 weeks :-)
Sorry, if I'm close to the goal I obviously won't meet your expexted delays ;) LOL
Hi C1 owners,
As long awaited, here's an update of my diagnostic tool project, and it is an exciting one :)
Thanks to club's diagnostic tool I manage to understand BMW C1 brain protocol and program my own circuit to communicate with it (see top of thread).
Now I know how to:
- get ECU and ABS informations
- read fault codes
- reset fault codes
At the moment the board is able to initiate communication and get ECU informations, it's just a matter of free time to program others functions.
As the communication protocol is a standard one (ISO14230) I have documentation on how to read real-time engine data (temperature, RPM...) but need to do some additional research.
That mean that I'm close to have my own diagnostic tool, autonomous (no pc needed) and in a big matchbox size!
To be continued...
Got the wired and removed it. In fact it's a plug that can be removed from the socket, so I recycle it for my diagnostic tool :)
So if you've got this plug, keep it for later use... :)
This plug just do a loop between DIAG signal and +12v, thus disabling any activity on the bus. (Activity is made by connecting GND to DIAG).
Hope it give some highlights
I sucessfully got fault code after unplugging Exhaust Oxygen sensor
However I could'nt produce any fault for ABS. What I did is put an aluminium paper sheet between coding wheel and ABS sensor and fire up the engine...
Any idea ?
Thanks! Any though for ECU fault code ? I was thinking of disconnecting lambda sensor...
OK, let me explain that geek's dialect...
The first electronic board has been designed to be as versatile as possible :
First, it will be programmed to record a conversation between a BMW diagnostic tool and C1.
Then as a modern Champollion I'll try to sort out those recorded hieroglyph to understand their meaning.
Once champollionized, I'll reprogram the board so it will be an autonomous diagnostic tool providing similar fonction as Clubs's GS911 or BMW diagnostic tool.
The second board allow a PC to speak to C1 using those hieroglyph... It is a low cost alternative to the first one...
I hope this explanation worst a try. :)
If you do not understand electronics, I know you understand this project potential benefits :)
Some updates on my project :
- Built a RS232 (PC serial but) to KBUS (C1 ECU) interface
- Built an autonomous MicroController board able to communicate on a KBUS (C1), display informations on LCD, store data (2x256k eeprom) and dump datas to a PC over RS232. It also feature an indicator leds and 4 push buttons.
Both are working OK.
Now I've got to hack C1 ECU protocol so I could code required software.
I can't wait for my turn on GS911 waiting list! ;)
This is first stage of the project : design a board to hack ECU protocol... I will develop a soft for this using C language (command line tool) so it'll be easy to port on other OSes.
Next stage will be based on an autonomous device with a PIC (Programmable Input Controller) and a LCD... But it's far from now!
Thanks, that's a kind offer in case I would screw up the one I buy on ebay. :)
The software is still to be written... Fortunately with my IT experience I can code C language :)
Maybe this will fail, it's a long way before I'll get the first results
Here are first pics of my BMW C1 diagnostic tool project!
I've got all electronic parts available and I'm waiting to receive a used ECU to start my first tests.
**BUT** first I'll have to move to my new house on thursday... and sort out the mess! :)
I agree that was a bit chauvinistic and not so partial, let's say that motorway and main roads are generaly smooth...
town and cities street are OK...sometime
and secondary roads are fairly average...most of the time
That's not seems to be the bopper but the front tyre :)
IMO 50000km seems fairly standard as my front one looked like new at 24000km (my first C1).
Moreover, roads in France are very well maintened and smooth... But maybe the point is about driving behaviour and how much ones uses its front brake ?
That's awesome, this looks like a tribute to my BoomBox special mod ! :)
Well done mate!!
I did, I don't want to screw my own BMS with my future project... ;)
I hope this one won't be screwed up by my experiments...
See the auction, I'm the winning bidder ;)
Hi Phil, I'm happy you get out of this crash in one single part :) but unfortunately your beloved C1 has been badly smashed.
I hope you'll get a good price from other party insurers and find another immaculate C1 as a replacement.
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