CEL on - no codes

[slvrspdr99]

Ok I'm stumped on this one. Check engine light is on no codes are present so there's no way to shut it off. I used my personal obd ii scanner and even the shops modis and both pull up no codes present so not being able to read codes isn't a question of equipment. Recent code was a p0300 for random misfire that only happened between 5000 - 5500rpm in 4th gear. Spark plugs and wires are new along with a valve cover gasket. It has been smoke tested and came out no leaks.

Thanks for any help

 

[Crazylilpunk]

I had a similar problem with a 2004 WRX STi. CEL was on, but there was no code. After driving with the car like this for a few hundred miles, the scan tool showed an emission code that was attributed to a bad front o2 sensor. Hope this might help!

 

[ForsakenLash]

have you tried clearing the light? Maybe unhook the battery for a min and see if it goes away? Or maybe if it comes back on it throws the code its reading?

 

[Cox Abele]

I'm dealing with a similar issue in my 98 with an H8 ECU shortly after tuning the vehicle with an OP2.0 cable and EcuFlash. I haven't resolved it yet either, but will let you know what I find once I reflash the stock tune.

Can you elaborate on your setup a little more. Year, ECU, is it tuned, what have you done to the engine management if anything?

 

[slvrspdr99]

Ok I'll see what happens if it doesn't go away. I'll try the clear option to see if that works. If not then to battery disconnection. Car is a 99 eclipse spyder 4g64 n/a mods are shift linkage related. Other than that it's factory.

 

[Albanator]

Check your evap system....sometimes if there is a leak it will not pull a code right away....

 

[slvrspdr99]

Well was able to clear the light and hasn't come back yet