Mini Cooper S ECU Issue (I bet know one can help)

[Jonathan English]

Hi guys,

Im new here and desperate for some help, I have posted this on multiple mini forums and the car has also been to multiple garages and an auto electrician. I am based in Essex if any of you guys are local and need some work! I have a cooper s with an issue and need help, as im not getting any luck on the mini forums yet anyway.... I have owned mini now for 12 weeks (5 weeks working 7 weeks and counting broken). However my sister today went to take it for a drive and see how it compares to her S. She started it up and instantly the battery light came on. I had driven it for 40mins to her house with no problems, stopped for an hour, then started it again. I thought it was weird but I said drive it anyway must be a dodgy battery or the alternators broken maybe. We drove for around 30secs and battery light went off. 2mins later engine light come on with the EML light. We pull over and the cars in limp mode. I tell her to turn it off and we started it back up at this point melting plastic smell and a bit of smoke comes through the passenger side vent area (I assume a wire has shorted somewhere?) We turn it off leave it for 5 mins and start it back up... No warning lights, no smell, absolutely fine... So we drive it back to hers... I get in it to go home and again start it and it's fine get 20mins up the road and it jumps into limp mode I pull over turn it off and start it again EML light goes out but the check engine light stays on.... I drive the remaining way home with the light on.

So i book it into a garage... they cannot connect to the ECU (all garage including myself can connect to the various modules via the port but NOT the engine modules to read fault codes), and recommend specialist with main dealer software, again they cant read it but recommend another garage, they have changed the battery, the alternator, and the replaced the ECU with a new cloned ECU.... Still not working and still not possible to connect to the ECU.... They recommend taking it to a tuning specialist.... and the good news is.... they cant fix it either.... So far i have spent, nothing at the first, (they told me they didn't have the technology for it) £20 at the second for a diagnostic, 470 at the 3rd + parts (alternator, batteryand ECU £450) and the fourth its cost £240 they also cannot find the problem, they have checked continuity on all ecu wiring, they have checked all the obd wiring, and cannot find anything, they have removed (some) modules, they even remove the k line wire and ran another wire to the appropriate port on the ecu, and still nothing, just as all the other garages... they again can read all modules except the engine codes.

The ECU light comes on whenever there is significant load, 1 week before the problems above i had an 18% pulley fitted and a larger intercooler, this i believed was bringing on the EML light on whenever you put your foot down, however, the next garage noticed that the crank pulley had split (4 garages did not notice this and one of them fitted the alternator and did not notice!)... this is what was causing the EML and has since been fixed and now the car runs and drives fine again which is great, however, the obd port still does not connect to the ECU.

I personally, have now stripped down the dash, I have power on pin 16 of the OBD and resistance on pins 4 and 5 and i get approximately 3.5v on pin 7. I have double checked for chaffing on the wires through the bulkhead, the grommet is in perfect condition and I cannot see any issues. Worth noting all fuses are fine also. from this point onward i am at a complete loss. The company that cloned the ECU could read the ECu fine on the bench, the original and the cloned both allow the car to run and drive they just cant be connected to.

If there is anyone that has any idea, please help me out

Thanks,

Jon

 

[Gazthesparky]

Hard to say without being in front of the car.

But this is a long shot I had a similar problem with my Audi a few years back.

My Audi wouldnt start every now and again and when I tried to connect to the engine ECU with the software it couldn’t find it. I thought that the ECU was goosed but stripped the car down to find that it was a faulty power relay. The relay provided power to ECU and if it wasn’t activating it wasn’t providing power to the ECU

So just a stab in the dark check for a power relay providing power to the ECU

 

[Jonathan English]

Hard to say without being in front of the car.

But this is a long shot I had a similar problem with my Audi a few years back.

My Audi wouldnt start every now and again and when I tried to connect to the engine ECU with the software it couldn’t find it. I thought that the ECU was goosed but stripped the car down to find that it was a faulty power relay. The relay provided power to ECU and if it wasn’t activating it wasn’t providing power to the ECU

So just a stab in the dark check for a power relay providing power to the ECU

Hi Mate,

Thanks for the reply! I will have alook and see if there is such a thing on the mini. I do however have one question... Did the audi run and drive fine even though there was no power to it? The problem I have is that for all intents and purposes, the car is perfect, just this stupid issue! I will have a google and see what i can find

Thanks for your help,

Jon

 

[static zap]

Still sounds like ,communications coming thru from ECU is getting blocked , may be by another device hogging the line .(or you have a devious short/damaged wiring /missed in buzzing out )
_Still worried did you find what burned up -- fear its wiring damage_

 

[Jonathan English]

My assumption was that it was the crank pulley failing and the belt slipping, caused the smell, although i cant tell this... 3 of the garages (and myself) have checked and cannot find any burning, also worth noting that the communication issue predates the burning aswell.

 

[SparkyChick]

If the cable is part of a loom (assuming it's wrapped in that fluffy fabric tape they seem to use these days), it doesn't have to appear burned to have smoked.

An overload could cause sufficient heating for smoking but not ignition. This may be very difficult to spot, especially if it's in a loom.

I would go through the fuse box and check all the fuses to ensure they are the correct rating and that none of them have blown.

 

[Jonathan English]

Hi Mate,

Thanks for your reply, again the garages (and myself) have all fuses in all the of the fuse boxes, according to this thread here they are correct. I have also changed all fuses that relate to the ECU/Canbus/K-Line just in case the fuse was faulty. I have also checked the wiring at the back of the main fuses box just in case the wiring had come loose.

thanks

Jon

 

[static zap]

Is it 2002 2006 model ,has a user way of seeing some data , via button presses ?
(and resetting all sorts--may include Comms data rate )

 

[Jonathan English]

Yea its the 2006 model. you can reset various bits you are correct, however the problem I have is that I am building it as a track car andits tuned as far as it can be without remapping.... Essentially to tack it to the next stage (cam, head, uprated supercharger etc.) but i need to be able to tune the ECU to go further, which obviously means the OBD port needs to work.

Thanks

Jon

 

[static zap]

Would be interested in results of "1.3" if dash is behaving !
MINI Cooper ECU Reset Procedure - R50/52/53 MINIs - https://new.minimania.com/ECU_Reset_Procedure___R50_52_53_MINIs