No the salad thing was todayWas she the one that ate your fellow mechanic’s chicken salad from the fridge?
Just wondering….
All I did was put a battery in it.
- Thread starter Chris142
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As a BMW's battery drains, the different electronic systems are supposed to go offline gracefully, just like a Windows computer shutting down - layer by layer.
Depending on how it went down, and as it was allowed to deplete itself completely, the different layers would shut down not in sequence.
The car would expect some systems to always have some power, even when the car is locked, and he battery fully draining would be like disconnecting the battery cable.
And you don't just disconnect the cable on a BMW, you first let it shut down. You put it in whatever mode it is that you use when disconnecting the battery, and you'd do that with a scanner, not through the car's menus, OR leave it with the key off the ignition and a door left open for what was it - eight or sixteen minutes.
Let a BMW sit till the battery drains and the least you can expect is a Christmass tree of lights and codes the first time you bring it back to life, which - hopefully and usually - clear out at the next engine restart. So the client shouldn't be too surprised.
Depending on how it went down, and as it was allowed to deplete itself completely, the different layers would shut down not in sequence.
The car would expect some systems to always have some power, even when the car is locked, and he battery fully draining would be like disconnecting the battery cable.
And you don't just disconnect the cable on a BMW, you first let it shut down. You put it in whatever mode it is that you use when disconnecting the battery, and you'd do that with a scanner, not through the car's menus, OR leave it with the key off the ignition and a door left open for what was it - eight or sixteen minutes.
Let a BMW sit till the battery drains and the least you can expect is a Christmass tree of lights and codes the first time you bring it back to life, which - hopefully and usually - clear out at the next engine restart. So the client shouldn't be too surprised.
not just BMWs, but any recent car with constant OBD monitors, telematics and keep-slices will do the same thing but not as drastic as a German car. Toyotas will run a EVAP check after a few hours and if the car has some gas in the tank. If you have JBL or Mark Levinson sound, the amp is in sleep mode until summoned.
No offense to independent shops, but if my 24 bmw has issues than bmw can figure it out. My wife’s 24 Nissan had a doa battery after we got back from a work trip. Of course it was pulled in frontwards in the garage at Detroit airport and I didn’t have a jump pack. I have one now no doubt. AAA got me going and I drove it straight to the dealer who had to do some diagnostics to make sure there was nothing else going on. They gave me a loaner and I picked it up the next day. They installed an agm which I guess is better than the efb.
Owen Lucas
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A diagnostic tech told me many of the German cars are very sensitive to minor voltage/resistance changes in connectors/wiring. It can happen for unknown reasons sometimes just when driving. This is possible during welding, but you are supposed to disconnect the battery. Any decent body shop (and repair estimate), should include a diagnostic before and after repairs. It's required for most vehicles, for the SRS system at least.
On a BMW, Mercedes, VW/Audi/Porsche, it’s recommended or mandatory to code the car for a new battery. On a VAG/Porsche product and if the battery is from the dealer, you enter the new battery’s serial number on a QR code. There’s reports changing the current serial enough is also sufficient to get the BMS/PMS to recognize a new battery. BMW and Mercedes wants to know the capacity in Ah and chemistry/type(lead-acid or lithium, flooded or AGM).
I totally forgot about this.
I test drove an early 2000s 528. They had to start it off a jump box. I jumped in and away we went. It ran very poorly, hvac didn’t work and just blew hot air, and it barely ran on 4 of its 6 cylinders. When I returned the salesman asked me how I went and i told him. He was very perplexed and went to start it himself. It fired right up, engine ran perfectly, and the AC sorted out the dash vents and blew cold.
My wife was so spooked we didn’t buy the car.
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Bingo.
Chances are the cooling fan was also blowing full blast the whole drive.
Car didn't "know" what the coolant temperature was so it went into some protection mode where fan was full blast, AC was deactivated and possibly engine power was reduced. This would be different from it "knowing" it's overheating, but the end result is the same.
Had to crank my 535xi that had sat parked for months for ten minutes when I bought it, and it acted exactly the same.
It's usually smart enough to not throw codes at the next restart, which is what happened.
This is not unique BTW, Peugeot/Citroën/Fiat minivans had that bug in the early 2000s where they needed a dealer tool to reset something if you'd let the battery drain.
About a year and a half ago I changed the battery in my fiancé's 2007 Mustang GT. I didn't accidentally short the positive cable to metal or anything like that. Once I had the new battery hooked up, the car was in a limp mode and the throttle body would not respond to pushing the pedal. The car would idle but would not rev up. It had several codes stored in the ECM relating to the throttle body along with some other stuff. There was no throttle relearn procedure for this car and I had changed the battery a couple of other times in the past with no issues. Prior to this battery change, there were no issues with the throttle body.
I did a lot of testing of the wiring and the voltages to the throttle body and everything was in spec. I reset the KAM and that did not work. Long story short, a new throttle body fixed the issue. The other stored codes were gone as well after I cleared them. I never did figure out why just changing the battery caused the throttle body to go out. Car only had about 32,000 miles on it at the time.
I did a lot of testing of the wiring and the voltages to the throttle body and everything was in spec. I reset the KAM and that did not work. Long story short, a new throttle body fixed the issue. The other stored codes were gone as well after I cleared them. I never did figure out why just changing the battery caused the throttle body to go out. Car only had about 32,000 miles on it at the time.
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Really it's quite a clever system, been in use for over two decades now in BMWs. It monitors the capacity and state of charge of the battery for a couple of reasons - regenerative charging for fuel efficiency in so-equipped models (EfficientDynamics alternator), health monitoring so that it can pop an error before you're left stranded, and it constantly calculates the percentage of the battery's capacity needed to start the car and shuts down systems so that the battery state of charge never crosses that threshold. Theoretically, you'll never be left stranded if you leave the interior lights on, run the radio too long, so on and so forth. The benefit of this is that you can have functions like interior ventilation with the engine off, roadside parking lamps, and so on without risk of critically discharging the battery.
In a normal battery swap, all you're doing is resetting the battery health/capacity monitoring to match the new battery. Another upshot is that if you change from a flooded to AGM or vice versa, you can change the charging behavior for optimal longevity in either case with just a button press.
I'm not one to praise overly complex systems, but I've never been left stranded due to a bad battery on a BMW. It will preserve the capacity of even a very bad one to where the car can still start, and the battery management seems to help them live longer in the first place.
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There's no dash message. A BMW that sits parked a lot has to be trickle charged - it's in the manual. But because most brands put that in the manual without meaning it, owners new to BMW don't know BMW actually means it. The owners that actually read the manual, that is. There was a mention somewhere on how often and for how long the car has to be driven to keep the battery alive and avoid a trickle charger, I think it was like an hour per week or something like that.
In normal driving, and in normal conditions with a healthy battery, the alternator only charges the battery on overrev & coasting (saves a few drops of gas, apparently), OR if the battery needs charging.
The main problem is that a BMW sitting with a weak battery does not always shut down all the systems gracefully as the battery goes completely dead, is all.
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Certainly a failed battery will leave you stranded, no doubt about it. I was more getting at the point that the car, within reason, won't let you run the fan or the radio so long that you don't have enough reserve to start the engine, which I think is a nice feature.
edyvw
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Yes, since 2004 BMW’s uses IBS. It is excellent system as long as you notice issues on time. If you allow battery to drop too much, all light on dashboard will light up etc. Many people then start chasing ghosts instead of just charging/changing battery.
edyvw
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Many people don’t lock their cars in garage. Unlocked BMW is still “doing stuff.”
I personally don’t lock mine as it is driven daily a lot. But if I am going somewhere for some time, it is absolutely locked.
I did a parasitic draw test on my 2019 Toyota just for funsies. It didn't make a difference locked or unlocked. It went way down but every couple minutes current draw spiked. I assume it was phoning home?
I would be interested to know what BMW is doing - just for curiosity.
