Check engine codes won't clear
Thread Starter
Member
Joined: Jan 2006
Posts: 178
Likes: 4
From: Austin, TX
2012 C250
Check engine codes won't clear
Hi all. I posted this in the W210 forum as well, but thought I'd post it here for more exposure. I have a check engine light on my 2001 E320. the codes I have are for cylinder misfires and fuel trim malfunctions. I have a MAF on order currently, and I changed the plugs recently. After I changed the plugs I went to autozone to get the codes pulled and cleared to see what came back, but for some reason the codes would not erase. the Code reader would display "clearing..." then come back with all the stored codes still there. Anyone have any thoughts why the P codes would not be cleared with a standard OBD reader? I'd rather not have to take the car to a mechanic or the dealer if I don't have to. 
Senior Member
Joined: Apr 2004
Posts: 393
Likes: 2
From: Mesa, AZ
2011 E350 Bluetec, 1996 S320 & 2006 E320 CDI Sold to my son & 2017 GMC 2500 Diesel Pick up
I have a code reader at home for my '96 S320 . when I clear a code and retest the code still shows up, but - if you unplug and start over replug re test etc. the codes are gone. Maybe that the same with yours. It was way confusing to me at first & have no idea why it seems to remember the code if not unplugged. Hope this helps.
Rod
Rod
Thread Starter
Member
Joined: Jan 2006
Posts: 178
Likes: 4
From: Austin, TX
2012 C250
So it appears I've found the solution to my own problem. It turns out that the people at Autozone weren't clearing the code properly. today I checked again and the code reader, while it's erasing the codes, prompts you to turn the car off. When the instructions were followed, there were no codes left. I'm going to let it run for a few days and see if the codes come back.
