Anyone know why ghost codes even exist? Why would Nissan not want us to know when certain things are wrong with out cars? Could it be becuase the ghost-codes problems aren't so serious? I've heard somewhere that when your CEL is on thje ecu automatically retards the timing a bit, is this true? Just a thought that poped in my head.

 

CEL lights are typically for emissions control malfunctions.

 

I guess Nissan doesn't want to give away ALL of their secrets;

I have been trying to diagnose a misfire problem for months, but after trying everything I could think of I finally went to a mechanic. I had NO CEL and codes always read 05-05.

Turns out there was a Bank 1 Fuel System (MAF) code stored; mechanic said that because my car is a '95, but the first of the OBD-II systems, there are some codes that will not set a CEL or self-diagnose flash-code, but are stored nonetheless. What other codes are like this?

 

well i know that knock sensor codes can be "ghost codes" and will not set off the CEL, but will show up with a self-diagnosis. I thought about the emissions part too Loe max, but wouldn't a ghost code still make you fail emissions?