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Hello, New member here.
We have owned our car for 1 year.
2016, CLS63 AMG S, 73k miles.
Trouble free except for have to change the tires for very loud road noise. Switched from Continetals to Michelins.
Now, intermittently, the car goes into a weird mode - pressing the gas pedal has no response. Trying to press the pedal harder makes the car rumble (like driving on cobblestone) and slows down even more. Sometimes the CEL light will come on. It cannot be driven this way. We have to pull over and stop the car. Put it in park, turn off the car, restart car, start driving and problem is gone.
It actually feels like the result of wandering onto the double yellow line on the road, and the cars sensors turn the car away from the yellow line, add a rumble to the tires and take away the gas pedal input.
I need to get a code reader, can I ask for any recommendations?
Thank you,
Patrick
Limp mode. The result of a misfire. Yes, you need a scanner. Scan for codes, note the location of the misfire and clear it. If it continues to happen on the same cylinder then it could be a bad plug, bad coil, or something far worse....
Hello, New member here.
We have owned our car for 1 year.
2016, CLS63 AMG S, 73k miles.
Trouble free except for have to change the tires for very loud road noise. Switched from Continetals to Michelins.
Now, intermittently, the car goes into a weird mode - pressing the gas pedal has no response. Trying to press the pedal harder makes the car rumble (like driving on cobblestone) and slows down even more. Sometimes the CEL light will come on. It cannot be driven this way. We have to pull over and stop the car. Put it in park, turn off the car, restart car, start driving and problem is gone.
It actually feels like the result of wandering onto the double yellow line on the road, and the cars sensors turn the car away from the yellow line, add a rumble to the tires and take away the gas pedal input.
I need to get a code reader, can I ask for any recommendations?
Thank you,
Patrick
I want to say I had the same exact problem about six months. Fuel pump went bad. When I pulled off the road, shut down car, waited five minutes, turned back on. Problem went away, only to show up again 5 miles down the road. I was able to limp to the mechanic for repairs.
Limp mode. The result of a misfire. Yes, you need a scanner. Scan for codes, note the location of the misfire and clear it. If it continues to happen on the same cylinder then it could be a bad plug, bad coil, or something far worse....
I thought is was bad gas when it first happened. But no, been through 4 or 5 Tank fulls of gas since first happened. Last time in happened was over a week ago. And that time the CEL did not even come on.
Every time it has happened, we pull over, turn off the car, restart right away and problem is gone.
I thought is was bad gas when it first happened.
But no, been through 4 or 5 Tank fulls of gas since first happened. Last time in happened was over a week ago. And that time the CEL did not even come on.
Every time it has happened, we pull over, turn off the car, restart right away and problem is gone.
Cycling IGN while safely parked does fix this soft-freeze nicely each and every time. Be safe with road traffic... stay off the Hwy!
You'll need to learn to display LIVE VOLTAGE WHILE DRIVING...
You'll want to witness if your recurring Limp-modes are triggered by voltage yo-yo bugging a core network bridge.
Pass or Fail ?
Let us know what FULL SCAN reveals.
Before trying any fixes let's pinch the root cause trigger.
Last edited by CaliBenzDriver; Aug 28, 2025 at 06:34 PM.
No scanner yet. The iCarsoft Ver 3 is not available at Amazon. Might have to purchase through ebay...
I cannot locate a voltage display using the cars dash.
Will need scanner, plugged in, to see the cars voltage while driving?
No scanner yet, been on travel.
Researched the different scanners:
1) Launch Creader Elite for MB, 2023, $115
2) 2035 Launch X431 Creader Elite 2.0 BBA OBD2 for MB, BMW, Audi, $159
3) iCarsoft MB V3.0 for MB, $200
Looking ahead to if the coil is bad, who to purchase from?
I have used Autohauz AZ in the past for older MB's I've owned? Maybe NAPA? Rockauto has Bosche coils?
Have not set a code since switching coils. Driven daily, even took several day trips, 600 plus miles.
However, there have been several morning excursions where the car did its problem thing, pushing gas peddle has shutter response like in limp mode - but no check engine light. After pulling over and stop and start engine, back to normal ...
Checked for codes, nothing.
So, this problem only has happened during the cars first run of the day. When it happens, speed is always less than 40 mph. It never happens again that day. And it can go many days in a row without happening. It has never happened at speeds above 40 mph.
I will look at driving with the scanner connected and see if I can display operating voltage?
Have not set a code since switching coils. Driven daily, even took several day trips, 600 plus miles.
However, there have been several morning excursions where the car did its problem thing, pushing gas peddle has shutter response like in limp mode - but no check engine light. After pulling over and stop and start engine, back to normal ...
Checked for codes, nothing.
So, this problem only has happened during the cars first run of the day. When it happens, speed is always less than 40 mph. It never happens again that day. And it can go many days in a row without happening. It has never happened at speeds above 40 mph.
I will look at driving with the scanner connected and see if I can display operating voltage?
Ok, you now have a trusted equal ignition sparks: well done every 50kMi.
... still issue without fault!
-- You could now suspect the fuel side:
Read your long-term fuel trims: lean or rich?
Read your Fuel rail pressure: 150.Bars?
-- Chassis voltage... low & unstable voltage can be quickly made good by running "Headlights: ON" to trigger a reliable 14.4VDC fixed voltage.
See if that step prevents your troubles from acting up.
Report your research.
Last edited by CaliBenzDriver; Oct 21, 2025 at 12:04 AM.
The problem has been happening since my last post. No codes during these times. Some of them we had to pull off the road and stop and restart engine to fix the problem. Other times we tried turning on the headlights, no help. Other times we shifted from comfort mode to S and to S+. During these shift trys the problem did go away without having to stop the car/engine.
Now, this week it happened on 2 different mornings. Turning on the headlights and shifting through the modes did not help. Then the check engine light came. Flashing at first then switched to solid on. After stopping and restarting the engine all was back to normal operation. And the check engine light disappeared.
Returned home and checked for codes with the scanner. Coil number 5 is now showing.
Last edited by Corvetteguy; Nov 20, 2025 at 11:21 AM.
The problem has been happening since my last post. No codes during these times. Some of them we had to pull off the road and stop and restart engine to fix the problem. Other times we tried turning on the headlights, no help. Other times we shifted from comfort mode to S and to S+. During these shift trys the problem did go away without having to stop the car/engine.
Now, this week it happened on 2 different mornings. Turning on the headlights and shifting through the modes did not help. Then the check engine light came. Flashing at first then switched to solid on. After stopping and restarting the engine all was back to normal operation. And the check engine light disappeared.
Returned home and checked for codes with the scanner. Coil number 5 is now showing.
This is progress being made because now you have 3X hard faults about this CAN-C disruption by ECU + TCU + ESP + EPS.
You have tried stable voltage with HL:ON with limited success.
I bet all these faults are STORED transients (not "Active") - Don't bother considering each individual fault as significant. Something is bugging down your CAN-C that gets reset by key cycle.
> Further progress /What to try :
I reread up your thread : I believe you have a good shot at a free fix by cleaning your painted ECU GND.
It seems the ECU is the initiator to this wholesale CAN-C chaos.
Locations are footwell + firewall + front beam.
Double check WIS schematic for exact locations.
HK-Style beautiful S-class: S350 base V6 sold by Zung Fu Ltd.
Last edited by CaliBenzDriver; Nov 21, 2025 at 02:14 AM.
What to try : I reread up your thread : I believe you have a good shot at a free fix by cleaning your painted ECU GND. It seems the ECU is the initiator to this wholesale CAN-C chaos. Locations are footwell + firewall + front beam. Double check WIS schematic for exact locations.
Sounds good, thanks. I don't have a WIS program to find the exact locations of the painted ECU GND'S. Any access to schematics online?
I will look at the car tomorrow to see if the gnd's are obvious.
Okay. The AllData is a subscription for a period of time. $20 for one month of use. I am uncertain of the information I will receive from them regarding my mercedes schematics? Will they have them and will I be able to save/print the schematics before the subscription runs out?
I am more willing to try a WIS purchase, most likely from ebay, $20-40. I have heard that these programs can be difficult to get to run on your computer...
Okay. The AllData is a subscription for a period of time. $20 for one month of use. I am uncertain of the information I will receive from them regarding my mercedes schematics? Will they have them and will I be able to save/print the schematics before the subscription runs out?
I am more willing to try a WIS purchase, most likely from ebay, $20-40. I have heard that these programs can be difficult to get to run on your computer...
you've good it!
one is easier but more limited
one is more professional and unlimited.
Perhaps try both or pick one only so long you get results. I'd pick WIS for accuracy.
Not only Mercedes are "Made in China", finest European style castles too 👏
Last edited by CaliBenzDriver; Nov 23, 2025 at 09:42 AM.
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