Start/Stop glitch
#1
Start/Stop glitch
So weird issue. After driving long enough for car to be at normal temp. (it was around 45f out side) I stopped at a light. Start/Stop engaged and after maybe 60 or a little more seconds, light turned green. Let off the break, and it felt like the start/start system took a little more time to start back up. Usually it is near instant that the engine pops back to life and I'm off. It felt more like a normal start. People with Start/Stop will know what I am talking about. The car feels different when Start/Stop turns the car on vs. a normal startup after a shutdown. The dash indicated RPMs limited to 3800, Start/Stop malfunction and will be disabled, and the EPC light came on. No check engine light. Car basically in limp home mode.
Was able to pull over, turn off the car, and back on. RPM redline led lights took about 1.5 seconds to move back over to the normal spot, and the car is fine.
I have had ONE other similar instance a few months back, where again with Start/Stop engaged, and then back on. This time it started up fine, but Blind Spot monitor malfunction- turning off. Pulling over, turn car off and then back on again fixes it.
Other than this, the car is amazing. Just speculating, but maybe the Start/Stop system is draining the start/stop battery to much before it decides it better let the car take over, and the car is in some kind of half way point of not being able to maintain all systems or what? Engine is fine, and am thinking the rough startup this morning tripped the computer into thinking something is wrong with the engine since it was expecting the car to be ready to go when the engine was busy being started and thus went into Limp Home Mode just in case? Again we are talking about 1 second vs. the normal .5 second start. So not sure how fast all the engine check sensors are and what kind of tolerance they have. Any ideas?
Was able to pull over, turn off the car, and back on. RPM redline led lights took about 1.5 seconds to move back over to the normal spot, and the car is fine.
I have had ONE other similar instance a few months back, where again with Start/Stop engaged, and then back on. This time it started up fine, but Blind Spot monitor malfunction- turning off. Pulling over, turn car off and then back on again fixes it.
Other than this, the car is amazing. Just speculating, but maybe the Start/Stop system is draining the start/stop battery to much before it decides it better let the car take over, and the car is in some kind of half way point of not being able to maintain all systems or what? Engine is fine, and am thinking the rough startup this morning tripped the computer into thinking something is wrong with the engine since it was expecting the car to be ready to go when the engine was busy being started and thus went into Limp Home Mode just in case? Again we are talking about 1 second vs. the normal .5 second start. So not sure how fast all the engine check sensors are and what kind of tolerance they have. Any ideas?
#3
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This does not sound at all like a battery issue. Suggest you take the car to your dealer to have it scanned. Or, if you know someone with a Vag-Com, they can scan for you to see if any codes were triggered.
#4
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So weird issue. After driving long enough for car to be at normal temp. (it was around 45f out side) I stopped at a light. Start/Stop engaged and after maybe 60 or a little more seconds, light turned green. Let off the break, and it felt like the start/start system took a little more time to start back up. Usually it is near instant that the engine pops back to life and I'm off. It felt more like a normal start. People with Start/Stop will know what I am talking about. The car feels different when Start/Stop turns the car on vs. a normal startup after a shutdown. The dash indicated RPMs limited to 3800, Start/Stop malfunction and will be disabled, and the EPC light came on. No check engine light. Car basically in limp home mode.
Was able to pull over, turn off the car, and back on. RPM redline led lights took about 1.5 seconds to move back over to the normal spot, and the car is fine.
I have had ONE other similar instance a few months back, where again with Start/Stop engaged, and then back on. This time it started up fine, but Blind Spot monitor malfunction- turning off. Pulling over, turn car off and then back on again fixes it.
Other than this, the car is amazing. Just speculating, but maybe the Start/Stop system is draining the start/stop battery to much before it decides it better let the car take over, and the car is in some kind of half way point of not being able to maintain all systems or what? Engine is fine, and am thinking the rough startup this morning tripped the computer into thinking something is wrong with the engine since it was expecting the car to be ready to go when the engine was busy being started and thus went into Limp Home Mode just in case? Again we are talking about 1 second vs. the normal .5 second start. So not sure how fast all the engine check sensors are and what kind of tolerance they have. Any ideas?
Was able to pull over, turn off the car, and back on. RPM redline led lights took about 1.5 seconds to move back over to the normal spot, and the car is fine.
I have had ONE other similar instance a few months back, where again with Start/Stop engaged, and then back on. This time it started up fine, but Blind Spot monitor malfunction- turning off. Pulling over, turn car off and then back on again fixes it.
Other than this, the car is amazing. Just speculating, but maybe the Start/Stop system is draining the start/stop battery to much before it decides it better let the car take over, and the car is in some kind of half way point of not being able to maintain all systems or what? Engine is fine, and am thinking the rough startup this morning tripped the computer into thinking something is wrong with the engine since it was expecting the car to be ready to go when the engine was busy being started and thus went into Limp Home Mode just in case? Again we are talking about 1 second vs. the normal .5 second start. So not sure how fast all the engine check sensors are and what kind of tolerance they have. Any ideas?
#5
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#8
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I honestly do not think you're (I have 2012 too, so I currently don't have it) missing anything with the Start/Stop. The 2013 A6 loaner I have right now has the feature and honestly, it is kind of meh to me. I do not see any substantial increase in fuel economy and one has to wonder what all that starting and stopping is doing to the system over time.
#9
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I suspect the Stop/Start function has more to do with emissions than with fuel economy. For one, it is programmed to only occur once the engine has reached a certain temperature - in other words, once the catalytic convertors are warmed up. Emissions are highest with cold starts - so a warmer engine does not have the emissions 'penalty' with repeated restarts.
#10
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The 2.0T is a nice alternative to the 3.0 and very much a "real' A6. Suggest you educate yourself a bit more about these cars -there are many options and reatures, and ALL of them are A6s.