OBDII code 303?
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Newbie
Joined: Jun 2015
Posts: 7
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From: Brunswick, Maine
2011 MB C300 4Matic Lux
OBDII code 303?
Hi All -
A little lost on this one. 303 code which I understand is a misfire (plus there were some random misfires). When I had the codes pulled by a local guy for timing and $$ reasons, he said it was a permanent code. He said he could not clear that code. I feel like this is a random issue. Can this be cleared to check?
I do not have the engine background to put pieces together like this... possible causes? Car runs fine, even when gas pedal is floored. Only issue I have ever had is a short bit of rough idle at start up - goes away in a matter of 10 secs. Thoughts and recommendations are appreciated much!
A little lost on this one. 303 code which I understand is a misfire (plus there were some random misfires). When I had the codes pulled by a local guy for timing and $$ reasons, he said it was a permanent code. He said he could not clear that code. I feel like this is a random issue. Can this be cleared to check?
I do not have the engine background to put pieces together like this... possible causes? Car runs fine, even when gas pedal is floored. Only issue I have ever had is a short bit of rough idle at start up - goes away in a matter of 10 secs. Thoughts and recommendations are appreciated much!
Member
Joined: Sep 2005
Posts: 82
Likes: 2
2014 C250
An OBD P0303 code is a misfire for cylinder #3. If you clear the code and it comes back right away, you may have a bad coil pack on that cylinder or the plug is really badly worn and misfires almost constantly. I have not had to clear codes on my MB before, but it should be the same as other vehicles. Might want to start with some fresh plugs and consider the coil pack if it still acts up.
Symptoms may include:
•the engine may be harder to start
•the engine may stumble / stumble, and/or hesitate
•other symptoms may also be present
Causes
A code P0303 may mean that one or more of the following has happened:
•Faulty spark plug or wire
•Faulty coil (pack)
•Faulty oxygen sensor(s)
•Faulty fuel injector
Symptoms may include:
•the engine may be harder to start
•the engine may stumble / stumble, and/or hesitate
•other symptoms may also be present
Causes
A code P0303 may mean that one or more of the following has happened:
•Faulty spark plug or wire
•Faulty coil (pack)
•Faulty oxygen sensor(s)
•Faulty fuel injector
Last edited by twowheelin; Oct 17, 2016 at 04:09 PM.
