strange: misfire and red alternator/battery
Thread Starter
MBWorld Fanatic!
Joined: Sep 2002
Posts: 1,719
Likes: 12
From: West
2005 E55 Wagon
strange: misfire and red alternator/battery
The strangest thing occurred this week. Out of nowhere, I got a CEL and "low batterty, no convenient features" at the same time. Car was running perfect, strong and no issues. Then, at highway speeds both warnings came on.
I charged the battery. I checked the CEL which showed random misfire and misfire on cyl 5-8.
I know from a search on this forum that a possible bad 02 sensor causes that type of misfire. Sure enough, a new 02 sensor resolved the problem and no more CELs.
After charging battery, I then got the red battery/alternator warning. I know from before that is the alternator. Had my indy shop change the alternator and all is good. No problems.
But, it is just strange. Out of nowhere, those two warnings problems came on and came on at the same time.
By chance, anybody else had this problem?
I charged the battery. I checked the CEL which showed random misfire and misfire on cyl 5-8.
I know from a search on this forum that a possible bad 02 sensor causes that type of misfire. Sure enough, a new 02 sensor resolved the problem and no more CELs.
After charging battery, I then got the red battery/alternator warning. I know from before that is the alternator. Had my indy shop change the alternator and all is good. No problems.
But, it is just strange. Out of nowhere, those two warnings problems came on and came on at the same time.
By chance, anybody else had this problem?
MBWorld Fanatic!
Joined: Nov 2007
Posts: 3,681
Likes: 39
From: San Diego
E55
The strangest thing occurred this week. Out of nowhere, I got a CEL and "low batterty, no convenient features" at the same time. Car was running perfect, strong and no issues. Then, at highway speeds both warnings came on.
I charged the battery. I checked the CEL which showed random misfire and misfire on cyl 5-8.
I know from a search on this forum that a possible bad 02 sensor causes that type of misfire. Sure enough, a new 02 sensor resolved the problem and no more CELs.
After charging battery, I then got the red battery/alternator warning. I know from before that is the alternator. Had my indy shop change the alternator and all is good. No problems.
But, it is just strange. Out of nowhere, those two warnings problems came on and came on at the same time.
By chance, anybody else had this problem?
I charged the battery. I checked the CEL which showed random misfire and misfire on cyl 5-8.
I know from a search on this forum that a possible bad 02 sensor causes that type of misfire. Sure enough, a new 02 sensor resolved the problem and no more CELs.
After charging battery, I then got the red battery/alternator warning. I know from before that is the alternator. Had my indy shop change the alternator and all is good. No problems.
But, it is just strange. Out of nowhere, those two warnings problems came on and came on at the same time.
By chance, anybody else had this problem?
Wow, random misfire 5-8 is bad O2 sensor? Probably would not have guessed that. You are talking about primary O2 sensor or secondary?
Thread Starter
MBWorld Fanatic!
Joined: Sep 2002
Posts: 1,719
Likes: 12
From: West
2005 E55 Wagon
It was upstream 02 sensor..the primary, I guess (before the cats). I found solution from doing a search on the forum. Others had same problem and got it resolved via new O2 sensor.
