While driving the car today i gunned it a bit to get around someone and mid acceleration it felt like an anchor was dropped. Took me a min to realize the motor died. pulled over and restarted 🤷‍♂️ I heard the little alarm and now know it did the accident avoidance braking followed by killing the motor 🤯

Anyone else have this happen ? That was super lame and annoying. potentially dangerous depending where it kills the motor. Was embarrassing but relieved to realize that’s all it was.

 

It definitely shouldn’t be doing this. Did you get a CEL?

 

nope. ……. Car has Eurocharge stage 1 tune but don’t think that would be connected. let’s hope it doesn’t happen again 🤞

 

The Auto-Braking feature can get wonky, and actually be dangerous in a situation where you need evasive maneuvering/quick acceleration on the highway, and on the track.

Can "Disable" it in the Menu for highway, but for Track, there may remain elements of the nanny, tightening up your seat belt suddenly, etc
Can try taping over all the front and rear bumper sensors, and the larger 3 Point Star sensor in front grill - this method has worked for some.

 

I set the dial to 3 reds seems to disable it 👍. not sure what i think about that “feature”

 

This feature should absolutely NOT kill the motor under any circumstances. A safety device that would deploy during a near miss, then deny you power steering and power brakes (BC the motor died) is not a safety feature, it's a death wish.

I see this differently. Knowing what I know about tuning and what is available to the tuner, the tune would be at the top of my list. One corrupted data table either accidentally, or sometimes via a corrupted download is all it takes. I know you're with a known aftermarket brand, but I've run across some real "tooners" out there that thought they knew what they were doing and didn't.

I am not suggesting the tune is the absolute fault, but for me it surely is a possibility.

 

You can work around it by turning off Active Brake Assist (https://mbworld.org/forums/coupe-roa...st-system.html). I don't think you should have to switch into track mode and mess with ESP each time you start the car.

But clearly there's a bigger problem with the engine dying, which definitely should not happen. I'd personally get to the bottom of that first.

 

Yes, agree with det000

Another possibility - try to get a deep scan done. You'll need a more sophisticated diagnostic tool. The complexity of the controller area network protocols in this car can cause controllers to dropout intermittently or partially. You can end up with one or more features that won't work as designed. With U-codes, you might not see any dash warnings or other indications there are faults occurring on the CANBUS.

I recently did a thread on this topic

https://mbworld.org/forums/coupe-roa...0-u103100.html

After a routine deep scan of my car, I found multiple CANBUS errors emanating from the AMG gateway module. There were no dash warning signs/messages of any kind, but I found some modules were not communicating or intermittent on the network. I went through the details of getting to the bottom of it in the above thread.

Maybe try a deep scan, but still don't discount the tune.

 

I defer to others more knowledgeable about what might be the issue here. For tracking, I would not recommend taping over sensors in case you forget to remove the tape on the road. You need to fully defeat the ESP by holding down the button for a few seconds until it's fully off. This will stop the Active Brake Assist and the pretensioning of the seatbelts. There's the added benefit of less wear on your rear brake pads, but expect to manually handle it if you get loose. It will reset to on when you restart the car.

 

I wish it was that straightforward but Accident Avoidance Braking and ESP are different systems.

 

Thanks Case. I am not interested in arguing and getting into any conflicts here. I simply want to enjoy the knowledge of others and try to pass on what I have learned. But your comment reminded me that Pre-Safe is a different system that tightens the seat belts. I often conflate this with the ABA since they are related, so I appreciate you reminding me. With that, two things:
1. Based on track experience, when you don't turn ESP fully off, ABA and Pre-Safe continue to operate. Try it. The rare times, I forget to fully defeat it, I am quickly reminded if I am late braking behind someone in a corner.
2. See page 61 of the 2018 owners manual as it says the following:Characteristics when ESP® is deactivated

If ESP® is deactivated and one or more wheels start to spin, the÷ESP® warning lamp in the instrument cluster flashes. In such situations, ESP® will not stabilize the vehicle.
If you deactivate ESP®:

• ESP® no longer improves driving stability.
• Engine torque is no longer limited and the drive wheels are able to spin. The spinning of the wheels results in a cut for better traction on loose surfaces.
• Traction control is still activated.
• Adaptive Brake Assist is unavailable.
• Active Brake Assist is also not activated if you brake firmly with assistance from ESP®.
• PRE-SAFE® is unavailable.
• PRE-SAFE® is also not activated if you brakefirmly with assistance from ESP®.

 

ABA only deactivates when you’re in ‘Race’ mode; you press and hold ESP to totally deactivate in; (being in ‘ESP Sport’ mode won’t cut it), and then you go into the DIC and manually turn off ABA.

Remember that you have to do the whole sequence above every time you turn off the car.

It’s a good idea to leave the TC with lots of Yellow lights showing initially until you get used to having ESP totally Off, but the car extremely balanced as long as you’re careful with your right foot.

 

Great info everyone. thanks.

I think i’ll get to get a deep scan and talk to the tuner and see if they have any insight.

Been to track once right after i got the car a few weeks ago. Played with car in Race and sport plus. Turned ESP off and had three reds. seemed to get rid of the ABA and the belt tensioning. car felt solid and predictable. On my C7Z I usually put it in PTM sport 1 and 2. tried race a few times and was non eventful but o like having the safety of active handling if i screw up. Sounds like with ESP off you lose MB version of active handling.