ASR light and no power!!!! - PeachParts Mercedes-Benz Forum

sab · #1 09-07-2003, 11:19 PM

I am cruising at 85 MPH heading south on the Turnpike back to Miami and everything seems great.
Suddenly the car seems to hesitate just a bit...
I play with the gas pedal a bit accelerate, decelerate between 75 and 90 MPH and it seems OK again.
OK, I am back to cruising speed and suddenly the ASR light comes on solid and it feels like someone uhooked my gas pedal. Absolutely no reaction and I am slowly loosing speed.
At this point I put the pedal to the metal and I am almost able to hold 50 MPH, but still loosing ground.
I gave up and pulled over placed it out of gear and it idled just fine ASR light still on. Slightly hit the accelerator.... NOTHING happens.
Well I shut it down getting ready to call a tow truck and in my desperation give it one last try.
It cranks right up and voila, there she goes as if nothing happened.
NOW is that strange or what?

Anyone has some insights as to what just happened?
Thanks,
Sab.

400E · #2 09-08-2003, 08:16 AM

Did you check your owner's manual? It actually describes this symptom ...

You went into "limp home" mode due to a fault in the ASR system. Many, many different things can cause this.

Do a search on "asr light" and you'll get some ideas of what's going on. You will see that you need to pull the codes to really diagnose this system.

arif · #3 09-08-2003, 12:25 PM

Steve
can you comment on this:
l periodically get the ASR light but the car still has full power and l can continue to cruise at 80-90mph! the pedal just has to be pushed a bit more but the engine runs fine.....does this sound like 'limp home' mode since still have full power? l limp home mode l understand you really lose power as the engine timing is thrown off.
very strange.
PS so far this has not happened frequent enough and l am waiting for it to get worse before getting diagnosed, l get Code 6.

JimF · #4 09-09-2003, 10:57 AM

the DTCs in the ECUs as in my thread. Without those, as 400E said, you won't know what is causing this.

Frank Dalton · #5 10-07-2003, 01:04 PM

See my thread or that of Mark Stetson below yours. I'd love to know how it works out. We've had this problem for awhile. It's got the local dealership working hard to find a solution, but the car is still in the shop. More news in a few days. Good News! I hope.

sab · #6 10-07-2003, 08:15 PM

Brought my car to an independent shop (finally found a great shop after beeing f***ed by the dealer for 5 years).
He diagnosed the Mass Airflow Sensor to be bad and the throttle actuator to indicate open throttle.
All was changed, car purrs like a cat.
Cheers,
Sab.

Frank Dalton · #7 10-07-2003, 09:41 PM

Sab... Glad it's working for you. Good Luck! The replacement of the mass air flow sensor was one of the first attempts we made to correct the problem. Ran well for a while then problem came right back... ASR light coming on while at highway speed and car going into limp home mode. Putting it in neutral and starting puts everything back to normal... until the next time. Same for replacing wiring harness. It usually seems to happen while going at least 50 mph and it can be scary on an interstate. Last time it threw off a code and now we're replacing the starter lockout and reversing lamp switch, We shall see. Regardless, from all the threads I've read, it seems that there is no one particular cause or cure and that there may well be multiple causes and, therefore, solutions. I think it's a matter of trial and eror, albeit, a very expensive trial! I'll post again after we've logged a number of miles with this latest "fix'.

Frank Dalton
94 500SL
00 500SL