Parking Sensor Failure 2 Red lights

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I have an iCarsoft MBii that shows the data from each individual sensor for testing.
I am happy to let you borrow it to help diagnose the issue.
All I ask is you pay for return postage (RM Special delivery).

Tony
Sorry to resurrect an old thread, but my PTS is being a PITA!

My iCarsoft initially diagnosed a faulty sensor, so I swapped it out, to no avail. I tried swapping sensor around, but still the same error was being shown. I have now also replaced the wiring loom, and now I'm not getting any fault code, but am still getting the dreaded 4 red lights! :(

I really don't need all this hassle on top of my health problems. Has anybody got any further suggestions? I'm about to go and give the sensors a gentle clean, before resembling the rear of the car, having taken off the bumper to replace the loom. Is it worth getting a control module and swapping that, or do I just admit defeat and get a mechanic to look at it?
 
Managed to get it out.

The sensor appears to have a silicone back to it, which is very squishy and oozes water.

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For future reference, here's the writing detailing the MB part number and the Bosch part number of the sensor for the S211.

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How did you remove the sensor? I have a 2006 s211 E 220 and as far as I can tell, to replace a rear sensor you have to take the bumper off.
Thanks
 
Control module would be my guess. Have had same problem with my E class and one of my ML's in the past , garage replaced both the faulty sensor and control module.
 
i have this same problem, i replaced all the front sensors then it worked fine for a couple of days and now it's started again.

Getting very frustrating now
In my case, the cause was a faulty battery. Installed a new one, everything works fine now
 
In my case, the cause was a faulty battery. Installed a new one, everything works fine now
I’m about to try that, E350 2013, it’s had a new rear battery so I’d say the main battery is due for renewal at 7 yrs old.
Park sensors work when you first start, but, if you drive 2 minutes? Not long at all, repark, they are no longer working??
If I turn ignition off, lock it, open it then ignition on again, they work again??
Sometimes it won’t start first time, dead, try again, all ok. Eco start stop rarely works.
also, main fuse box had a few crushed wires where it’d closed with them trapped. Not sure whether to change the crushed bits or not because on certain cars some things work on electrical resistance?
My gut says to change, solder heat shrink etc a patch.As im typing, thinking I might just pull the insulation back & bridge it to check?
They are low amp, thin wires. Going to a plug in the fuse box.
I have the battery, so going to swap it. I had similar spurious faults on my Sprinter, changed the battery (seemed ok though?) all worked well after. Not bad connection previously either.
good luck
Ps. The boot (estate) something seems to open on it’s own? Trying to work out if that’s 10 stone of dog accidentally stepping on the key or whether it’s connected to electrical fault?
 
Hello

My new GLE bought the brand new in April. Noted about three months ago that front park sensors, when the car first started just the two red lights come on, beep and turn off the parking system, and work once I have switched off and on. I thought it was me parking front first up, near garage door, it was intermittent. Recently I have reversed car onto the drive and the last couple of weeks, again intermittent problems, get two red lights on front sensor, loud beeps and stops working until i turn off the engine and start.

Should I book a visit to MB as I hate waiting around. Btw, the car sensor are clean, I'm the only driver and no damage is noted to the sensors.

Thanks
Hi There,

I recent have the same problem with my 2015 GLE. Have you sort out and find what is the problem?
 
I had this problem before when the garage disconnected my battery,took it back and they reset the sensors with the diagnosis machine.got it come back again now this cause I think my battery is shite
 
Don't rule out wire corrosion as the true fault. I puzzled with the intermittent failure of an outer rear Parktronic sensor on our 2010 ML W164. The fault persisted even after swapping out the rogue sensor for a new one. Bumper off again. But by now the fault was obvious. Two wires had corroded and snapped off the sensor plug. Ideally the entire sensor wiring harness would be replaced. But Mercedes want £103.42. Instead, the sensor plugs are available separately for under £1.00 from China. They are compatible with VAG plugs (part no. 1718653-1). Plug replaced a month ago. Problem not returned.

Incidentally, Mercedes have used two different types of sensor for the w164 M-Class. On older cars, a fatter, rounder sensor with four pins (A0045428718) and on newer cars, a slender square type with three pins (A2215420417). The plug shown below is for the three pin Parktronic sensor.
 

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I had the same problem on my ML. Got cheap Mechanics Stethoscope and checked them all. Rear left one turned out to be quiet not ticking when you bring stethoscope probe near to it. Replaced it with Bosch from amazon seller and all working fine.

When checking make sure ignition is on and for rear ones the gear stick must be in reverse. The ticking sound is very clear when using that tool so if there is no noise then it is faulty. One faulty sensor will disable the whole system.
Having read this and others about using a stethoscope and listening for the ticking…. I did just that. I also bought a set of 4 Bosch sensors on line.

My rear parktronic on my 2009 S211 (eclass 280cdi estate) were not functioning. Read the posts did some mechanic stuff and I now have fully functioning parktronic… here’s how for the less mechanic minded…Start car, handbrake off, put in reverse ( 2 red lights on rear display bar and a peep), turnoff engine. Reds lights still on, reversing lights still on. With the stethoscope touch the centre (must be the centre) of each sensor from the outside and in my case they click 3 times repeatedly. One didn’t. Unclip the whole sensor and electrics attached, they are easily accessible on the S211, swapped it out. Restart with the stethoscope, it is now clicking as others are.

I now have yellow lights and then with a rubbish bin behind I tested both sides reversing and I now have fully functioning rear sensors. It took me 10mins start to finish. I just have to spray the sensor silver… and hope it doesn’t furgle it.

Thanks for the post on listening to the sensors you are great 👍😘
 

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