Quote:
Originally Posted by gaffasbm
hello . I am having some issues with my auto stop start . Auto stop start has stopped working for 3 months now on my e90 2009 lci. i have done a full read out on my scanner and the brake vacuum sensor is at fault. I have searched the net and this seems to be a common problem with this part failing . I had booked the car in with my local bmw specialist . Now this guy is a ex bmw master tech . He ran his own diagnostics using ista and again came back to me that the brake vacuum sensor is at fault . Now let me add that there was no warning lights on the dash at all fault was only appearing on diagnostics.
The tech tried to find the part on etk using my chassis number and the part at fault (vacuum pressure senor ) was in grey on etk as if its not available on my car. hmmm how strange .
so the tech had removed my original sensor to order the part using the part number on the original part 34 33 6 786 746 this has been superseded to part number 34 33 6 875 605. This part was then purchased from bmw sytner and the very next day fitted . After the part was fitted and ignition was switched on straight away a waning light would appear on the instrument cluster that the stop start was at fault. He then ran diagnostics to find that the new sensor was coming up as brake vacuum sensor short to positive.
The tech had checked the wiring going to the sensor and reported that the wiring was OK .So now we suspected that the new sensor must be faulty , so we returned the sensor and reordered a new sensor again from bmw . The sensor was changed the following day to have the same warning message as the previous new sensor . we tried a third new sensor and again no luck.
The tech then decided to do a software update on the DDE thinking this would fix the problem . After doing this the JBE module ( junction box Electronics) had failed and needed to be replaced at a cost of 470 quid and re-coding .
I bought a second hand sensor off ebay with the original part number as good used working condition 34 33 6 786 746 and this cleared the faults . when i drove the car home from the garage i noticed the car did not at all stop start . so when i got home i connected my foxwell 644nt pro diagnostic computer to the car to find the same fault under dde Brake vacuum sensor fault currently not preasant . i cleared the fault drove the car around the block and retested to again to find the exact same fault.
I am so confused to why this is not working.
before all this had started i had a water leak in the battery box where the 2 positive cables was submerged in water. could this had possibly spiked the ecu which could be causing my problem .
has anyone else had the same problem as me . tech and i are completely confused to why this is happening .
All reply's appreciated thanks  |
UPDATE!!!! Problem solved....
So its been over a week now . i sent the ecu off for testing to a company in derby ecu testing. once they got my ecu the next day they phone me up to say they couldnt test my ecu. That now had me so confused to what to do as a next step. Today i got my ecu back . i decided to test the wires going to the brake vacuum sensor from the ecu . I was extremely surprised to find that the wire at the plug for the sensor was broken . this was giving a short to positive reading on the diagnostics . i did a quick fix with some solder and walla all working codes reset and stop start now working as it should . Quite pissed off with the master tech who supposedly had checked the wiring as now i see that he was talking out his backside.
