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Collision Prevention Assist Plus Inoperative!

86K views 24 replies 15 participants last post by  Richard Duley 
#1 ·
Only 4 weeks and 1000 miles into a fairly happy relationship with my GLA, but then this pops up! Anyone else get this? Bringing her in tomorrow. Also, only getting 19.8 mpg overall (granted, mostly city)... anyone else see such disappointing MPG?
 

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#4 ·
Just back from the Mercedes Service Dept. and they said it was a "software" update to fix the Collision Prevention error, but no one could tell me if the software update included any sort of transmission update... Nevertheless, the DCT shifts "seem" a bit smoother and my MPG coming home were the best I've seen since owning the car... Maybe there is a much needed transmission software update available now.... can anyone else confirm??
 
#7 ·
AMGz, I did ask my service advisor, but he could not confirm that the software update did or did not include a transmission fix.... Frustrating, but the error message was fixed and after 15+ miles, MPG and shifts seem improved... I'll report back after a week or so, hopefully with a positive report on both.
 
#8 ·
Owned a gla250 4matic for just under 2 months. Have about 4000 mi on the clock. Was out on the freeway on Saturday in a rainy day when this message (CPA+ INOPERABLE) popped up on the cluster in front of the steering wheel).

Have an appointment with the dealer on Wednesday. Will let you know what they find out. ..

This feature is important to us as this car was an alternative to a Subaru with Eyesight...
 
#10 ·
My car went into limp mode twice when driving at speed in the rain on the highway in July and created a check engine light. The dealer said they did something with the software. It drives a bit less smooth, no mileage difference and the check engine light was cleared. I wonder where water is getting that would cause electrical issues. I had to stop and turn the car off and back on to get the transmission to function.
 
#12 ·
Still not back yet. .

The fault croped up 2 days after installing the front license plate.

So in the meantime I've had the following uneducated questions. Yes it's ok to call me a dumbkof.


I think there's some kind of training phase for the RADAR.

I wonder if it has learned a particular waveform shape and stored it to memory.

Now would the detected waveform shape have changed due to the placement of a us metal license plate in the center of the front bumper? ?

Maybe if the detection controller is not able to detect reflected waves of the right shape for days it throws a fault? ???
 
#17 ·
This is quite alarming to me. How many ppl out there might have zero idea that their CPA is faulty.
I for one am not too impressed with this system. It works here and there, but never for objects other than cars. I ran a few tests while driving on a busy street and intentionally drove up to numerous cars (tailgating if you will) and this system kicked on once.
I am now wondering if I also have a faulty CPA ?
If so, would anyone know my best coarse of action to get the dealership to follow through with an inspection ?
 
#20 ·
This happened to me again last Friday. I stepped on the gas to clear an intersection and got inoperative error message and the car was reduced to idle with no response from pressing the gas. Luckily I had enough momentum to clear the intersection and had to shut the engine off and restart it, after which the car operated normally.
 
#23 ·
FWIW my car showed the “Collision Prevention Assist Plus Inoperative” error and the dealer determined the cause to be a faulty brake light switch. They replaced it under warranty this morning.
 
#24 ·
This could be important info. Mine started this nonsense a couple days back, putting foot on brake to move to reverse to get out of garage. Car has not seen any rain and is not driven much. Could care less what it means since I don't need collision assist, and if you are paying attention in front of you I'm not sure the value of this. No time to take it back to dealer for this anytime soon. Tech to me generally sucks, I'm sure lots of other brands have their issues. The more wires and computers, sensors you have running around, they will fail. Tech is certainly good, but I don't go after cars for how much crap tech they have in them.
 
#25 ·
I was nearly rear ended pulling onto the freeway unable to accelerate and could have been killed because of the collision prevention inoperative problem. I have had my C300 in the Mercedes Dealership at least 7 times. Now Mercedes Benz of Sarasota wants me to pay over $2,000 to once again fix the collision prevention inoperative problem. They guaranteed me the last time they fixed it that it won't happen again. I wonder if someone else has already been killed because they could not accelerate when driving onto the freeway with this collision prevention inoperative problem. Mercedes doesn't care they get their money and you die driving their cars.
 
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