I wanted to share a recent experience with my 2017 GLC 300. I was driving away from a stop light and accelerated to about 30 to 35 mph. A car stopped in my lane to make a left hand turn. As I approached the car I applied the brakes but the car did not slow as expected. I stabbed the brakes to the floor at that time and the car gradually reduced speed to about 20-25 mph. I was freaked out and tried to move into the right lane but traffic prevented me from doing so. With the pedal to the floor the car kept approaching the Altima in front of me. About 20 feet from the car, the car made a sound and slowed to 8 to 10 mph and then impacted the car in front of me. The trunk and bumper of the car in from of me was damaged as was my hood, bumper and plastic fascia. Once I hit the car, I noticed a warning on the dash that indicated the brake assist was inoperative. Thanks for the warning!!! I waited for roadside assistance and had it towed to a MB dealership. Interesting to note that the rotors were still too hot to touch more than 45 minutes after the incident.

MB NA is investigating and we will see what the find. The dealership service manager has indicated that they did find a fault from the brake assist that referenced a problem with the ESP. I have asked for all of the logs but they refuse to share them with me while the investigation is underway. I am frankly concerned about the safety of the vehicle at this point. If they can't point to a specific point of failure, I am not sure I would be comfortable driving it again.

I will see what MBNA does at this point. Please let me know if anyone else has experienced anything like this.

 

If it indeed was the fault of the car, I'd be looking into some legal action to prevent the cause of the accident going on your driving record. In the long run that could cost you more on insurance than the cost of the repairs.

 

I spoke with MBNA again today to understand the timeline. They indicated it was a matter of "weeks" for any resolution. After an undefined number of weeks they would render their decision and let me know the outcome. I asked if they would share any data before or after the event and the answer was no. They would share their decision.

They also highlighted that the loaner was provided by the dealer and could be pulled back at any time. They indicated they were not responsible for providing alternative transportation and to contact my insurance company. I was feeling a bit upset at that point so asked them to provide me a copy of the policy in writing. He indicated that it was not written down and they could provide nothing in writing ;(

So much for a greater customer service experience. I understand they have a job to do but it makes me feel a bit helpless to know there is no clear timelne, no information will be shared and nothing will be provided to me in writing.

I have asked the dealership for what they will give me for the vehicle in current condition. It is paid off so whatever I can get I will use for a different brand of vehicle. In parallel I have reached out to an attorney to see what my options are for protecting my interests.

 

You can likely blame the legal system for this. Right or wrong, MBNA is protecting themselves from litigation.. at least that's probably what their attorneys are advising.

 

I would suggest you do not mention lawyer or taking legal action to the dealer or even here as someone from MB may monitor the board. Once they feel there is a threat of legal action, although in the end may be warranted, they will stop 100% of any communication with you. Best to just wait and see what comes of the situation. I know its not what you want to hear. Glad you weren't going faster and everyone is OK. Cars can be fixed.

 

Very good point. You can seek consultation but stay mum about it.

 

One last update. For the first time the NA Customer Service Rep called (actually three times in rapid succession). So I thought he had good news. I called him back and he indicated Mercedes had reached a conclusion that the brake had never been applied and that the brake assist worked as designed slowing the car from 37 to 17mph in 1 second. I pointed out that did not align with what the other person (who was hit witnessed as she looked in her rear view mirror at my daughter frantically trying to stop). A couple of other points. 37 to 17mph in 1 second would be a deceleration force of 2g which I doubt the GLC is capable of. Second, the damage in the pictures does not indicate a 17mph crash...maybe 7. The response from Mercedes was they would do nothing and they deemed the car safe. They have still refused to release the diagnostic data going as far as to explicitly instruct the dealership to not provide me with any information. Mercedes refused also to refund the unused maintenance agreement.

So I sold the GLC to the dealership for a loss of about 10K. I purchased the new Q5 to replace my daughter's car. I still strongly believe the GLC we had to be unsafe and I will continue to seek the release of the data. For anyone who does purchase this vehicle, you should be aware of the issue experienced with MB NA and their analysis that the car performed as designed. The VIN is WDC0G4JB4HF119871. In the event that the subsequent owner has any issue, I hope they find this post. More than this, I hope that no one has to experience this situation at all

 

I'm confused, were you driving or your daughter?

 

My daughter was driving the car and I recounted her experience in my first post. This was as she described it to me and what the other person described who was hit. I spoke with her prior to the insurance settlement. Apologies for any confusion. I should not have written it first person in my original post.

 

OK, makes sense. Thanks.

 

Just curious--how did the person in the car that was hit determine that your daughter was frantically trying to stop?

 

All around a crappy situation.

Just to remind you brakes are a vital safety system and they do not instantaneously fail. You will be able to feel, see, or hear warning signs.

No clue if your dealer is covering up something or if your daughter just didn't apply the brakes because of panic. But I would be interested to see the service log.

 

Maybe you need to consider the possibility that your daughter made a mistake that she is not admitting to!

 

Maybe so. The car has an event data recorder. If Mercedes' analysis of that data revealed that the brake was not applied, that is basically dispositive and it will be hard to prove otherwise.

 

Agree. How old is your daughter? The story does not make sense.

 

I'm puzzled by the reported brake failure and hot rotors 45 minutes after the occurrence. The two are not compatible.

 

Agree with Larry. The story does not make sense. I think there is more to this story.

 

You say the vehicle was "towed" to a dealer.
Do you actually mean towed or was it placed on a truck/trailer?

 

Good questions and comments. I will do my best to answer. My daughter is 22 yo senior at UT. I trust her to tell me the truth in such things and I have no reason to doubt her about an accident that cost less than $2000 in damage for both parties. What helps bolster her story to me is the amount of damage as shown in the photos that indicates a low speed collision which differs materially from the speeds indicated by the customer service advisor (17mph).

The car was brought to the dealership on a flatbed that we called through roadside assistance. It stayed at the dealer until we disposed of it. The dealership would not work on it until the decision by MB NA.

Even though I sold the car I have repeatedly called to get access to the diagnostic data. As of today, the customer service representative indicated that he was unaware of the email to the dealership forbidding them from sharing any diagnostic data (which was told to be directly by the MB Service Manager at the dealership on Saturday). I indicated that this contradicted what was said on last Thursday's call when he indicated the data would be released after the decision. Lastly he said, it could be that policy has changed since last week and that I might need to acquire my own tool to read the EDR as it is not a given that MB would allow access to the data. Read "the best or nothing" in terms of customer support

Confusing to say the least. I would just like the data to examine at this point. I agree the combination of the OBD and EDR data should provide much more insight but at this point they simply indicate they have to send another email to legal requesting clarification.

I get the suspicion that kids might lie. It is always a possibility but I don't think so in this case. She loved the car and did not want to change. She is certainly not an Audi fan. In the end, the insurance estimate for the MB repair was $720. Such minor damage as to almost not be noticeable. But she was terrified of driving it given the experience so we made a decision.

Ultimately the car may not be at fault but I want to see the data to come to my own final conclusions.

 

When in Panic, many a time people unknowingly apply Gas instead of Brake. Even experienced drivers commit that mistake sometimes. It may be possible that Gas was applied instead of Brake and the Collision Prevention System was trying to slow the car down continuously. That may also explain heated rotors.
Just a theory if you actually finds out from the log data that Brakes were not applied.

 

If the rotors were hot then the brakes had to be applied. They either heat up because your foot is on the brake or the CPA had quicked in. On the W205 forum Fabrisd1 who works for a Mercedes dealer describes how CPA and brake assist works. It tells what happens with and without your foot on the pedal.

 

Well... I am grateful that your daughter is OK - and frankly running into a stopped car at her "35mph" speed WITHOUT Collision Prevention Assist + - combined with Brake Assist would have been a HECK-OF-A-LOT more than $2,000 damage to both vehicles.

If she doesn't feel safe with her car now - for any reason whatsoever - as a great father of course you changed her over and put that as most important.

The GLC does not have a flight recorder - what you had was the combined action of Collision Prevention Assist + which alerted her to the impending collision situation - and when she hit the brakes in a panic stop - yes - when Brake Assist takes over it does "feel" solid brake pedal" because that system takes over and maximizes the brake force for her panic stop.

As you say - discs were hot - from those safety systems doing their job - it grabbed the brakes - and you have not reported skid marks so all systems including ETS performed admirably.

Whatever I have to say - or you will say to your daughter - NOTHING will make her feel secure again in the same car she had her major scare in.

As a father - your daughter was accelerating directly towards a stopped car - and the safety systems caught that - and minimized the damage to $2K for both cars.

I suspect after your daughter "hit the brakes" - yes Brake Assist kicked in with "solid pedal fee" - she may or may not have lifted/pumped brakes again - and Brake Assist would have kicked in again when she pumped back down - at that original speed - without that instinctive pump action - yes it is quite possible full stop under 1st brake assist might have well brought her to full stop - but a "pump" can be instinctive when feeling dead pedal.

Scared - YES - Saved from major damage or injury YES.

She will be a better/safer and more alert driver now - after her scare.

Your former GLC does not have a Data Recorder - there is a open Mercedes PTSS case on that GLC which was requested by the dealer based on your reports that your daughter reported a malfunction braking system - which is a Mercedes Product Technical Support Services case - where that GLC will be held to the side until a PTSS MB technician gets to that case to instruct and authorize the dealer to do partial mechanical tear down of select systems to confirm systems did act correctly without hidden issues.

Sorry this happened - glad your daughter is safe - unless PTSS show something different in 6 weeks or so - frankly your MB save everyone from major damage or injury.

No foul on having to move on to the next vehicle..

 

As an engineer (albeit electrical), I have to admit what you have said is very possible. I was not there and I will have to believe my daughter's account until MB releases the data from the vehicle to prove otherwise.

Based on her feedback, she did not pump the brakes but pressed them to the floor more than 5 car lengths before the stopped vehicle. The MB CSR indicated the car was not accelerating so it was not an incident of pressing the gas versus the brake. The data as quoted by the MB CSR of a 37 to 17 mph deceleration in 1 second and 17mph impact does not align to the physical evidence.

Again this is information from the CSR and may not align exactly with the final report. I look forward to getting this information and I have told MB NA that I am happy to pay for the service if that is the issue.

I apologize if this comes off as angry or reactionary. I am not angry...simply frustrated. It is a learning experience that, unfortunately, will forever effect my perception of the brand - not from the incident itself but from the customer service experience afterwards. At this point, I simply want the data and the written report from MB. Will happily share with the community at large regardless of what it indicates.

Many thanks for the thoughtful comments and suggestions

 

Ummm...
I think Occam's Razor would apply to this scenario.

 

She was terrified of disappointing her dad.

Have you checked her phone history prior and during the accident. I have a shiny nickel that says she was online or texting leading into the incident.