Arrie

Just a note on the batteries.

The big one in your trunk is the main battery that starts the engine too. The other smaller battery hidden somewhere else (mine is in the driver side end inside dash) is the auxiliary battery and when this one goes bad it can cause issues with Parktronic, Distronic, etc.

I learned about this with my 2010 E550 that has all these gizmos.

So, a low cost way to rule out the AUX battery being the culprit is to have it replaced. I replaced mine myself. Battery was about $65 from the dealer and about 40 min work came from my own back.

BOTUS

that's not quite right. depending on the age....
early ones 2005 to mid 2007 25kg toys battery in the boot, smaller 15kg one at the front starts the car
first face lift, moved to one large battery in the front
by 2012 there are ones with another silly battery and a module for the start stop that just goes wrong

Arrie

Well,

perhaps my thinking is wrong BUT, in my understanding the size of the main battery is determined by the need for Cold Cranking Amps (CCA) to get the engine going in very harsh cold temperatures.. This is the main reason for the huge battery sizes in the cars. The electric gizmos in the car need very little power compared to hundreds of amps that the car starting pulls from the battery and for the moment of starting most of the gizmos and other electric devices are disconnected from the starting main battery so all battery power can be used for starting the car. The smaller AUX battery then is used to keep the gizmos alive during starting and if this AUX battery fails it causes issues with the gizmos like Distronic or Parktronic etc.as they go powerless or to very low voltage during the engine start-up.

I experienced this with my E550 when the AUX battery got old and failed during engine start at cold weather. All gizmos went inoperable until I stopped the car and re-started it. Restarting the warm engine takes mush less amps so my gizmos worked fine after re-start. AUX battery in my car is very small fist size lead-acid battery and they all have life span like the main batteries do.

I'm not sure how these two batteries are electrically connected in the car. I think the AUX battery gets charging from the main battery but the current does not flow in the other direction so that when car starts and main battery voltage goes down the smaller AUX battery keeps voltage to the gizmos unless thy AUX battery is weak and voltage drops with the main battery voltage.

But, perhaps I'm wrong and the smaller battery is the starter battery. This would not make sense to me though but perhaps that's just me...?

corkshoppe

i have a my 2013 s550, and while driving with curise on, every now and then my car goes into a tail spin and slow down, i turn of the cruise and look around for a ford and sure enough there will be a ****ty little ford in front of me causing all the problems!!!!! dealer said no fix! and its not just older ****ty fords but newer ones as well.

BOTUS

I have never had this, there are certain sized panel vans in front of you any brand that cause issues, standard cars and standard lorries NEVER do this if the beam is headed the correct way....

the set up of the radar is supposed to be critical - that's a myth - mine was way too far left (we drive on the correct side - so for you - that would be looking 25% of the time, in the right lane beside you) making the ghost vehicle incidents much more prevalent...
note where each three screws are on the main radar and go quarter turn away, moving the beam from the inside lane back to your lane....
then turn the display on and note what it see's when closely following cars with traffic in other lanes.... you can mostly tune out that wayward behaviour

DaleB

Things may be different in the UK as far as what equipment is delivered on new vehicles from the factory, frequencies used, etc. I don't know what you folks see in terms of blind spot assist, lane keeping, all of that. All I know is that I have experienced the exact same issue with the car braking sharply once in a while in cruise on the highway, and it is ALWAYS -- 100.00% of the time -- when passing certain Ford vehicles, usually an Explorer or Edge. Nothing else. It's relatively rare, but it happens.

I've learned to anticipate it and have a foot ready on the accelerator pedal to override Distronic.

BOTUS

Dale, my car used to do this ALL THE TIME with any vehicle on my left (which would be your right when driving on the wrong side), but always more of a reaction when it was certain panel vans. I had seen from the service history at various points it had had three "minor scope perform" operations, which is a some radar set up procedure by the dealership. However my disctronic plus was hopeless.

Having had Radar cruise on a BMW that was much better, less stupid, faster reacting and with better logic. I knew the radar beam rubbish Mercedes gets paranoid about is just rubbish. In the BMW manual, it even says the owner should regularly check the radar is pointing the right way...

with the Mercedes' hopeless performance, the dealers obvious inability to fix and BMW saying DIY, I did exactly that. And transformed from an annoyance every 10 seconds, to once in a while on random road trips. In the end I moved the adjusting screw more than a turn and a half (actually 3 of them meaning that all argue with one another), so its more in to my lane. You can see progress by toggling the display in the instrument cluster and checking how it performs as you make small adjustments Half the problem is its pathetic refresh rate were the BMW was instant, the Merc takes about 1 second to react to anything.

Also found in aftermarket diagnostic tools (supporting ADAS) there's a drive down the road calibration sequence for these cars... So would be well worth pointing the main radar in you own lane, then doing the calibration.

I also spotted some interesting fun early in these cars life...

I wonder if in the states it could be metal number plates on the front and the last one about parktronic may be another part of the fun you get ?

P-B-54.65/130a FEB07 Parktronic triggers without obvious cause at the front bumper. This may be caused by the side edges of the license plate being detected as an obstruction by the PTS sensor. The system may trigger at the front at random. Due to varying license plate widths, the actual width of the license plate bracket will need to be coded if no faults are present or stored in the Parktronic control unit.

P-B-30.30/65 DEC07 “Distronic Plus – mph” displayed within the IC when attempting to activate and/or “Release Parking Brake” in conjunction with acoustic warning and automatic release may not possible. The airbag control module will be replaced. In order to permit activation of Distronic Plus, the ABR control unit requires that certain prerequisites be satisfied, such as the signal that the driver has fastened his seat belt. The airbag control unit provides this information.

P-B-42.45/71a JAN08 -- 221 up to VIN A126228 and 216 up to A005109 “ESP/BAS Defective” or “ESP/BAS Visit Workshop” displayed in the instrument cluster (IC); wiring harness to passenger- side wiper motor may be chafing and requires repair.

P-B-54.65/194a MAR08 If Park Assist indicator bars do not extinguish (over speeds of 10 mph) or Park Assist does not function this may be due to the software in the radar control unit. Software will be updated.

DaleB

It's not the aiming of the Distronic radar. This is quite simple -- radar interference from some other specific makes/models of vehicles, and it doesn't matter which side they're on. Yesterday we went to visit my wife's parents, about 85 miles each way. Mostly Interstate. I'll use that as an example.

• Pulling up to a stop light in town, most of the time everything is fine. Then on one occasion I get the "PARKTRONIC INOPERATIVE" message as we come to a stop. Late model Nissan in the next lane, as usual -- it's almost always a Ford Explorer, Ford Edge, or a Nissan Pathfinder. Occasionally it will be a Subaru. Turn of Parktronic, that ends that problem.
• On the highway, cruise set. We pass a late model Explorer, he's on my right; car starts to brake sharply as we approach and get into his blind spot. Kick Distronic off and override, as son as we pass him everything is back to normal.
• On the way home, there's a Nissan SUV again. This time we're in town but still on the Interstate, so you have mixed speed traffic in all three lanes. He's in the left lane, we're going around him on the right side. Car brakes heavily again as we approach his blind spot, maybe 30-40 feet behind him. Other traffic moves into the lane ahead and makes it pointless to pass him; I drop back and get in directly behind him. Distronic is fine with this and maintains following distance without complaint.

I believe, based on where we are in relation to the other vehicle when this happens, that it's the blind spot radar in these vehicles. It's always one of a very small number of makes and models that does it, and it doesn't matter whether they are on the left or the right. I can pass a thousand other cars, pickups, SUVs and trucks without incident, but there are certain ones that will set it off. It's gotten to where I can tell ahead of time when it's going to happen, and I usually just kick the cruise off until we're past. In city driving, whenever I remember to do it I just disable Parktronic as siin as I start the engine... if I forget I'm almost always reminded fairly soon, as there are a ton of Explorers in town.

NONE of the symptoms you listed in your last post happen to me -- ever. It never happens "without obvious cause"; the cause is radar unit interference from other vehicles. For the Parktronic issue, DAS will even show fault codes for all four front radar sensors experiencing interference from other radar units. For the Distronic issue, it was a mystery until I noted that there were always the same culprits nearby when it happened, and it's always just as we come into range of their blind spot sensing system.

BOTUS

Your first point is the parking sensor feature and doesn't impact cruise control at all. The next two points are faults on your car, and you can fix inside 2 minutes at home. The cruise control faults happened all the time on mine 5 years ago, but seldom do now... its wrong reflections hitting your radar (because your main radar is pointing in the wrong direction) and you car is just reacting as it was programmed to do. You need to change that wrong behaviour by moving the main beam so its JUST in your lane, not theirs as well... drive in similar conditions before and after adjustment you will be shocked at the change.

As is, pre realignment of the radar - the car can't cope as its getting information from the wrong places.
Move the main radar 5 degrees further in to your lane - (rather than 1/3 pointing in the lane that causes the "ghost reactions"). Note post change, ghost reactions reduce from all the time and potentially dangerous, to rare incidents of very mild hesitation you can safely ignore.

After adjustment go for a drive and observe a difference in behaviour.
Post adjustment, on the instrument cluster, as cars move out of your lane they now drop off the image quickly and or as they move in to your lane, they appear quickly.... As you straddle lanes it reacts to vehicles directly in front of you, rather than ones to your side.
And better still when driving the car it behaves and "ONLY mildly reacts to ghost vehicles of a certain design". Usually certain model Panel vans 50 yards in front in the lane beside you. And or any Panel van and an Artic (and or some Estates and an Artic).

Blind spot detection is incredibly rare and you can see this activate on the door pillar of other vehicles. This has never caused my car to react. Ghost reactions on mine are mostly from old vehicles that never had this feature or any other ADAS electronics

DaleB

Jesus, I give up. You just don't get it. I am perfectly well aware that the Parktronic issue (which is most definitely radar interference from other vehicles) is unrelated to the Distronic issue -- which is ALSO most definitely, most assuredly, and provably NOT an aiming issue. If it were an aiming issue, it wouldn't be so selective as to happen ONLY in the presence of certain makes and models of vehicles. Believe it or not, I'm not a complete idiot. I've tested various things to see if the Distronic radar is "seeing" cars in the wrong lane; it's not. And it never happens with a delivery van, straight truck, or semitrailer.

Maybe blind spot detection is "incredibly rare" where you live. In the US, it's damn near standard equipment. MOST of the more well equipped cars and SUVs -- and that's a LOT of vehicles -- have it. My wife's 2016 Volvo does; my father in law's pickup does, as does my mother in law's Lincoln, my sister in law's car, and about half the other cars owned by family members. If it's less than 5-6 years old, there's a fair chance it has blind spot detection. This is especially true of SUVs, which means about half the vehicles driven in this part of the country and tend to be very well optioned since they're essentially the new luxury family sedan.

I'm done arguing about it, though. You do you, have a nice day. I'm out.

BOTUS

it is.... move the beam and test !

if you do half a turn you can easily put it back exactly where it is (if you want it to misbehave after you've fixed it).

its precisely wrong reflections causing it, which is why ordinary cars don't do it

lkchris

purpose of auxiliary battery is to ensure transmission can be shifted out of park when main battery fails. The little steering column lever controls an electric solenoid.

Arrie

It has something to do with other functions too, like Distronic and Parktronic.

BOTUS

on the old e class w211 (not on S w221) there is an aux battery to make the nasty dangerous SBC brakes function in an emergency....

there is a difference between
an 8" x 4" x 8" (motorbike style) aux battery
the 15kg (starter) battery
and the 25kg consumer (toys) battery

my fathers e 211 has the motorbike one for the brakes and the same 25kg battery but it does everything else
as far as I know I have only 2 the front 15kg one and the 25kg one in the back, later models then went to no rear battery and I guess ones with stop start got a small aux battery (like many of the modern ones do)

megacrazy

I think both of you guys are right. I agree that certain vehicles cause interference with the park sensors. I have the same issues when I come to a stop light and it's ALWAYS a car with ultrasonic park sensors in front of me or close to me. No ultrasonic sensors = no issues.

I haven't tried the cruise control feature much but the misalignment theory seems right. Of course you wouldn't know if sensors are interfering with it because the parking sensors of other cars should be off at high speeds. Distance might also be way too far for the sensors to be effective in jamming the main radar.

BOTUS

Radar bounce ? tesla introduced radar bounce to get the beam to go under the car in front and look at the next one...

what I noticed when moving mine... the more you move it, the more you impact the other dimension you didn't necessarily want to touch.... move sideways get up down in to the bargain.... so you have to start mixing and matching settings.... over the 18 months I did mine I lost track of what I'd done... about a year after I first moved it and was quite happy with the improvement, I was after more of an improvement.... so gave it another more aggressive tweak in to my lane (that again helped reduce ghost vehicle detection) but straight away I noticed a significant change in the distance it was reacting to other vehicles (from what I'd done it could only have moved the beam down) so I then I suspected its too low.... but didn't get why that would make it react earlier.

"luckily" it was around the time tesla had just introduced that bounce feature in software and it was on my mind. So tried to tweak the up down settings and what I noticed is there's a significant change in distance detection when there's small amounts of beam height movement... point it down and it reacts earlier !!!! (exact opposite of what you want) I suspect it bounces the beam and manages to travel further / faster - thus braking earlier / at distances it shouldn't....

A few days after the recent post Dale got excited about, it got me thinking about why "ONLY" certain vehicles do it... That gets me to quite how it determines the back of a car vs the front, which I don't know.... unless its just doing something with own vehicle speed and what's happening to the one in front??? Or and what I'm trying to say... I think if the height is less than perfect, it may create more reflections from the sides / tops of certain tall vehicles in the surrounding vicinity …. and as its not really understanding what they are, it errs towards safer early reactions?

On the BLIS idea..... (blind spot detection) I thought the first person pointing this out said when his stands on the brakes needlessly, when this happens if he looks behind him he notices there's a Ford there. Surely BLIS looks behind so how can your car looking forward detect their system.... unless he meant after he's passed the car that gave a "ghost" reaction he discovers in his "mirror" its a Ford.... which begs the point why not look on his door pillar as you pass to see if its even enabled ????

megacrazy

I don’t think it determines the back or front of a car from radar “imaging”. I think it simply does a speed comparison. If you’re not approaching the object In front faster than your own speed then clearly it’s a car moving in the same direction you are.

Blind spot detection or other parking sensors have a lot of bounce so it doesn’t matter where the car is when you’re sitting at a traffic light. Your own sensors might see some interference. The sensors will detect the interference and go into safe mode. After a certain time out they reactivate again.

I think a quick solution to the problem would be to have the system off when the car is started and manually activate it when needed. The loud beeping really annoys me. Or maybe decrease the severity of the alarm on the instrument cluster. You’d think the engine is about to fall out when that goes off.

BOTUS

The ABR beep I don't even notice, the Parktronic getting upset is a very unpleasant nag.

If it were as simple as doing a speed comparison. "If you’re not approaching the object In front faster than your own speed then clearly it’s a car moving in the same direction you are." How does it know to ignore parked cars? It seems to know the other is moving too.... and in the same directions and I'm not sure how it does that?

megacrazy

Well it the radar bounce matches the speed of the car then the object is not moving. As far as cars coming towards you or driving in the same direction I don’t think it really matters. Only the approach speed between the object in front and your car matters. I am assuming the confusion happens if the radar beam is misaligned and it hits an oncoming car and then the car in front of you in quick succession, confusing the system because of the large difference in speeds. It depends how they coded it.

I do have some ultrasonic sensors around. I’m gonna play with them when I have time see if they interfere.

DaleB

Ultrasonic sensors won't interfere with radar.

lionsfan54

Correct. But "full speed" active cruise control uses parking sensors below a certain speed to keep you moving. There's a handoff of sorts at about 15-20 mph

DaleB

I don't know about your car... but mine uses radar for parking sensors, too. No ultrasonic, period.

megacrazy

Shouldn't. But maybe the cars with said ultrasonic sensors have other sensors as well.

The sensor used for cruise control operates at a different frequency (77GHz) than the shorter range radar parking sensors. The sorter range ones should run in the K-band (24GHz). Plenty of interference on that band. From supermarket doors, to other radars to basically everything. The failsafe from Mercedes to shut it off and throw red text on your screen and sound an air raid alarm is a little much for my taste. I think the system should toggle to off when you turn the car on....and you should have to activate it as necessary. As it is now, it's the other way around.

I also thought the system was supposed to shut itself off next to airports and such, to not interfere with radar around there. Has anyone actually experienced this?

megacrazy

Oh and here's a table from a NHTSA paper on radar interference. If you read through the whole thing it basically confirms what we are saying here. There also seem to be no standards that are followed to stop interference. Car makers buy radar units and assume that the manufacturers tested for interference. Radar manufacturers do not work together. So yeah....nice.

When you guys are messing with the beam adjustments you might be polarizing the beam compared to incoming LRR, reducing the interference.

LRR= long range radar
MRR= mid range radar

Scenario 1: incoming traffic with LRR
Scenario 2: multiple lane congestion (2 cars in passing lane with LRR)
Scenario 3: side by side/getting passed by 1 car with LRR
Scenario 4: incoming cars with LRR and somebody backing out with MRR
Scenario 5: approaching somebody with SRR (blind spot radar)

Arrie

How do you shift transmission out of PARK if the engine is not running? I have E-class and S-class and I have not been able to find a way for getting transmission out of PARK if engine is not ON.

I also know that some well equipped car towers use a "double bearing" hub that they mount in place of one of the rear wheels or perhaps one also in front for AWD cars that allow the axle to turn backward when towing the car with transmission on PARK.. Why would they have this device if the transmission can be shifted out of PARK with the AUX battery or also with the main battery?