A/C On = inability to stop and shift smoothly for you too?
07-08-2008, 06:58 PM
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As some of you may have read in my previous posts, I've been plagued by the inability to stop smoothly as well as transmission jerk/hesitation since day one. The issues bothered me so that I took the car in for service last week (ended up with the 167s 
.) The dealer's master tech drove the car and admitted that there was harsh braking. He speculated the problem was due to the Comfort Stop (?) system, thus contacting BMW about retroactively removing the function from an E60. BMW's reply was that a program update was in the pipeline to allow for this, and it should be out in September...Last night, I'm driving with the A/C off and to my amazement, every stop was smooth. I repeated my experiment today (A/C off) with the same results. Smooth stops and less transmission jerking in Sport. Of note: RPM idle w/ A/C on = 700, A/C off = 500. I phoned my SA who said the software update would fix this issue too. Is that even possible? My question is if any of you experience the same thing? I understand that turning on the compressor causes a higher idling RPM, but is that at the expense of smooth stops and shifts for the rest of you? Do you think I need a second opinion? Sorry for the length.
Jason
.) The dealer's master tech drove the car and admitted that there was harsh braking. He speculated the problem was due to the Comfort Stop (?) system, thus contacting BMW about retroactively removing the function from an E60. BMW's reply was that a program update was in the pipeline to allow for this, and it should be out in September...Last night, I'm driving with the A/C off and to my amazement, every stop was smooth. I repeated my experiment today (A/C off) with the same results. Smooth stops and less transmission jerking in Sport. Of note: RPM idle w/ A/C on = 700, A/C off = 500. I phoned my SA who said the software update would fix this issue too. Is that even possible? My question is if any of you experience the same thing? I understand that turning on the compressor causes a higher idling RPM, but is that at the expense of smooth stops and shifts for the rest of you? Do you think I need a second opinion? Sorry for the length.Jason
07-09-2008, 01:25 AM
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My Ride: 2005 535d Sport
Very interesting.
My 530d shifts smoothly, but it's impossible to bring to a stop smoothly - like the transmission is still loaded up. I've never tried it with the AC off. Will do today and report back.
My 530d shifts smoothly, but it's impossible to bring to a stop smoothly - like the transmission is still loaded up. I've never tried it with the AC off. Will do today and report back.
07-09-2008, 04:18 AM
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My Ride: 545i
Model Year: 2004
Engine: N62
Funny you mention this. I noticed the same in my 04 545i. The issue seems the most prevalent when the AC is on. It feels like I am braking and hitting the gas at the same time.
07-09-2008, 07:04 AM
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My Ride: 525d E60
found this on google:
comfort stop (dive reduction under heavy braking) as part of the ABS systems.
Don't know what it really does. Suspect a smooth calliper pressure reduction at standstill or something like that.
comfort stop (dive reduction under heavy braking) as part of the ABS systems.
Don't know what it really does. Suspect a smooth calliper pressure reduction at standstill or something like that.
07-09-2008, 09:35 AM
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My Ride: 2004 530i 6-speed Titanium Silver/Black Interior
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I have found that with the AC ON, revs drop faster... makes it harder to shift smoothly (manual transmission)
07-09-2008, 09:43 AM
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My Ride: 2008 550i Jet Black on Black Leather, SAT with Paddles, Logic 7, Comfort Seats, NAV, Sport Package, PDC, Xenons, Sirius, Trinity 12W LED Angel Eyes, RPi GT Exhaust, M rear spoiler, ACS Roof Spoiler, Tinted Tail Lights, Bimmian Carbon Fiber Pillar Trim, Bimmian Shadow 550i emblem, RPi Scoop, E60 Forum Cling, Mtec bulbs in fog lights, Mtec 2W LED for License Plate Light Bulbs, K&N Filter, Bimmian LED Smoked Side Markers, Blackout roundels, Carbon Fiber Kidney Grills.
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Originally Posted by Hyper_545i' post='619378' date='Jul 9 2008, 05:18 AM
Funny you mention this. I noticed the same in my 04 545i. The issue seems the most prevalent when the AC is on. It feels like I am braking and hitting the gas at the same time.
07-09-2008, 08:41 PM
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Thanks for the replies thus far. So, the general consensus is these cars (particularly V8 models) don't have smooth braking capability with the AC on. Has anyone had success reversing this trend? I'm headed back to the dealer in the coming days for another look. I'll update with any developments.
