ECU Replacement Required?
 

Background: 2009 JCW 103k miles, CA car, running fine until one morning, the car went into limp mode and was without power... died a couple of times even in limp mode.Once home (where it saw over the next couple of days) it would barely start and I only managed to get it running a couple of times..

Pulled code P0190 (fuel pressure sensor), bought and replaced with new part and car cranks hard, but wouldn't start. Doubled checked the fuel pump (even gave it a good old whack, just in case) and still no dice. Checked code again and this time it showed P163E (Voltage Monitoring Control Module Communication Error). I pulled the ECU connectors and blew/cleaned both ends, but no dice.

I'm leaning towards the ECM/DME/ECU failing, but want to see what you think and see if I'm heading in the right direction. Other observation/symptoms the car currently has that kinda clue me in to ECU failure are: BMW/Mini code reader randomly reboots or goes blank while connected to the car (I made sure it was tight) like it lost connection to the car, other minor errors have thrown codes once or twice (such as gauge cluster issues, seat belt warning, and a couple of others - I can't recall the codes) when I cranked the car. I could clear these no problem. Another weird thing is when cranking, the digital display below the speedometer intermittently blanks out.

Battery is strong @ 11.75V (see entry below). Fuel @ 3/4 tank, ambient temperature 40-50 F

Hope you can share your 2 cents! Thanks!

At 11.75 Volts...the battery IS NOT STRONG. Should read mid 13 volts when running and at least mid 12 when sitting.
Probably start by trying a new battery.

That's odd, as I've always had 12V plus/minus even when new, at idle. I replaced my starter mid-2018, too.

I have the battery on a tender as well when I don't run the car often.

the starter has nothing to do with battery voltage or charging....I'm going to suspect a bad battery, bad cable connections, bad alternator...or a combination of all three

Bryan

LOL I added the starter for clarity, since I forgot it in my first post.

BTW, the battery is 5 months old.

Still, would any of these explain limp mode and the two big error codes?

I have seen bad "brand new" batteries right off the shelf.....our cars are very picky about proper voltages.....

Again, have the battery tested by someone who knows how to test a battery correctly, not those high school kids behind a parts store counter. Have your alternator tested as well, not by those same kids.....check your cable connections and your ground connections......

Don't assume you have a bad ECU....those rarely fail, and you don't want to buy one if it's not the problem

Bryan

So what you guys are saying is that the preceding error codes that sent my car into limp mode and now the 2BD0/P163e that won't clear are symptoms of any combination of the alternator/battery system?

Maybe. Maybe not. But given the rarity of DME failures and the cost of a new one -- I believe used can't be reused/reassigned to a different car -- making sure the battery is good and the alternator likewise just makes sense.

UPDATE
My battery was at 12.2V idle today and I cranked it, but doesn't turn over. Displays don't dim while starting (usually indicative of weak battery or starter), but a couple of warning indicators show on tach gauge LCD (but not physical lights in said gauge, except for check engine light), such as ASC/DSC with small exclamation next to it, and seat belt warning.

Codes 2BD0/P163e still remain.

I read somewhere that connectors along the wiring from the ECU/DME to the harnesses may have oil on them. I might look for that tomorrow and see if I find any and clean with electrical contact cleaner and rag.

:confused: This is probably the first time I've had a Mini issue where I just don't know which direction to head to in terms of a fix.