I've recently had check engine light codes thrown for cylinder misfires. I changed my plugs and went back to autozone to get the codes pulled/reset. When I tried to reset the codes, the tool they were using said it was erasing the codes, but for some reason the codes stayed. Does anyone know why the check engine codes would not erase using a standard OBD II tool? I'm driving a 2001 E320 with 92000 miles..
I too recently had a Multiple Misfire error code after getting a rough idle and the dreaded CEL. Auto Zone read and cleared these for me so my experience was that a Multiple Misfire error was NOT a hard error code.
As for checking the plug wires - use a multi-meter that and check the resistance in each... there should be little or none.
so, is a cylinder misfire inherently a "hard code"? or are there degrees of cylinder misfire about which I need to be concerned? Also, is there any reliable way I can test the spark plug wires myself?
To a degrees of cylinder of misfired. " hard code" usually will trip the "limp mode" to protect the engine from damages. The cheap hand held code reader from Autozone will not be able to reset the code.