Hey guys,

I've got a P0420 code throwing a CEL on my car, after awhile I noticed it went out and I thought the bulb burnt out. Ordered and installed a new one and it was fixed and then after about a day it was out again. It will occasionally come back on if I hit a big bump and then go out again at some time later. Very strange. When I put the new bulb in I didn't see anything that raise any suspicion to any wiring issue with the cluster and the bulb locked in as it was supposed to. Anyone have any ideas?

 

What makes you think it is the bulb and not the actual CEL code itself that makes the light come on?

 

When I turn the key the CEL doesn't illuminate.