ahmedalalousi

Boys and Girls,

I've a Bosch ME2.1 ECU (Bosch Part Number: 0 261 204 857, Mercedes Part Number: A 023 545 69 32).

While debugging a throttle body issue, I've isolated it to the ECU and took it apart. There are signs of physical damage at the underside of the PCB where an SMT resistor or cap has burnt and exploded beyond recognition. Apart from that, there are no other signs of damage. I have attached photos of both PCB sides, as well as a photo of the damage I'm referring to.

Tracing the tracks, it looks like it's feeding a Bosch 30359 driver IC.

I have so far failed in finding any images of the PCB to try and determine whether the damaged component is a resistor or a cap. I have also failed to find any data on the Bosch 30359 driver IC, except that a replacement is obtainable from fleeBay and other sources.

Would some kind soul please post PCB photos, IC data ...etc?

Grateful ..

Ahmed.

timmins

The fried component is sitting between some signal, likely a supply rail, and ground. I'd wager that's it's a cap. I would attempt to clean up the charred area using PCB cleaning solvent, and use a multimeter to check whether the damage has caused a short between the ground plane (the solid area connected to one of the component pads), and the "other" pad. If so, clean it up with a scalpel.

If you're lucky, the component might just be a decoupling cap used to reduce noise on the signal. In that case, you'll likely get by with the component missing.

It's possible the component damage is an indication of another problem on the board, in which case you're stuffed. It's also likely to have been caused by jump starting, or some other erroneous electrical event.

Good luck,
Tim

ahmedalalousi

Thanks for this input Tim.

Managed to obtain an image of the PCB underside of another unit from elsewhere, and it is indeed a cap. I've also been able to closely compare the Bosch driver chip with its Motorola counterpart; identical capacitor placement and values.

The Moto device, with the same number of pins, has an internal charge pump. I'm hoping to determine whether this cap is the 33nf sitting at the input to the charge pump or 100nf ceramic cap which is the part of the decoupling network at the supply line of the chip; I'm pulling the PCB away from the casing tomorrow and will keep the thread live with updates.

As to the IC, there are a number of supplies offering it for varying prices ranging from $10 upwards, so even if the driver stage is cooked, it's repairable.

Be really useful if someone with an ME2.1 or ME2.8 ECU could post a real close-up shot of both sides of the board for reference.

Thanks again,

Ahmed.

housew

so it looks like this same thing happened to me.

housew

did you ever figure out what the function of that cap was? Or what circuit it was on?


I'm getting my ECU replaced, BUT I'm weary of it happening again and want to make sure my car external of the ECU is in good shape so it doesn't foul another one.


My car was jump started ~4 times in the days prior to the ECU crapping the bed (or the car stopped running). If that was the cause I'm cool with it, at least I know, BUT if its coil packs back feeding or the like I like to test before plugging the new one in.

illest

i have always heard its not a good idea to jump start benzes because it could mess up the electronics. I had to jump my old w210 several times but never had any major issues. hope you get it figured out.