E350 stopped while clearing codes..
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Joined: Jan 2017
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W108 3.5 - 2005 E55
E350 stopped while clearing codes..
Yesterday I hooked up my Star laptop to a friend's E350 to check for ECU faults.
It reported two. I forget the number, but the description related to the LH and RH O2 sensors being out of range at idle.
While the computer was busy clearing the codes, the engine stopped.
We tried to restart it many times, and it would run for one or two seconds and then stop.
We thought maybe the CPS had failed, but the chances of that happening at exactly the same time we were clearing codes was unlikely.
In desperation we disconnected the battery for 5 minutes, but that had no effect.
We eventually managed to start the car by keeping the throttle open, but if we took a foot off the pedal it would stall again the first few times, but slowly got better with successive attempts. My friend took the car for a drive and it came good and drove perfectly.
My only explanation is that for whatever reason, this car needs a little more fuel than normal to to idle properly, hence the O2 sensor codes at idle. Possibly clearing the codes erased the idle mixture BLM adjustments previously learnt by the ECU?? I'm guessing when it started for only 1 or 2 seconds it was running on the startup enrichment.
Once driven, and it went closed loop, the BLM tables were relearned/repopulated and it was happy again.
That's my best guess.
Does this sound reasonable?
Anybody else experienced this?
THANKS!
It reported two. I forget the number, but the description related to the LH and RH O2 sensors being out of range at idle.
While the computer was busy clearing the codes, the engine stopped.
We tried to restart it many times, and it would run for one or two seconds and then stop.
We thought maybe the CPS had failed, but the chances of that happening at exactly the same time we were clearing codes was unlikely.
In desperation we disconnected the battery for 5 minutes, but that had no effect.
We eventually managed to start the car by keeping the throttle open, but if we took a foot off the pedal it would stall again the first few times, but slowly got better with successive attempts. My friend took the car for a drive and it came good and drove perfectly.
My only explanation is that for whatever reason, this car needs a little more fuel than normal to to idle properly, hence the O2 sensor codes at idle. Possibly clearing the codes erased the idle mixture BLM adjustments previously learnt by the ECU?? I'm guessing when it started for only 1 or 2 seconds it was running on the startup enrichment.
Once driven, and it went closed loop, the BLM tables were relearned/repopulated and it was happy again.
That's my best guess.
Does this sound reasonable?
Anybody else experienced this?
THANKS!
