So my check engine light is on, but it shows no codes when read!!!???

2 days ago I had the codes read and it showed up as IAC and TPS... I removed the throttle body and cleaned everything then reassembled. After that the check engine light went off. So I drove it round for a bit, no light. Parked it, no light. Re-start, and there it was again the check engine light. So I immediately went to have the codes read and it came up "No Codes Found"....!!!!

Its a 99 Cherokee Sport, 4.0, 5 speed manual.

Any Ideas???

 

Did you reset the computer?

 

The whole time i had the throttle body off i had the battery disconnected so the computer reset itself, yes...

 

Any ideas from anyone????

 

Have you tried a different code reader?

 

No, I had the same guy and same code reader at Autozone...

2 days ago the codes read for the IAC and TPS, like i said i cleaned the throttle body and everything really well, reinstalled, check engine light went out, then drove and parked, restarted and light was back on so i went back to AZ...
The same guy from 2 days ago with the same code reader and it came up "No codes found"... The autozone guy didnt even have an explanation other than "Thats wierd, ive never seen a check engine light on but have no codes.... Ive never seen a cherokee thats a 5 speed, I like it!"...

 

Any ideas from anyone???

 

Did you check to see if there were "soft" or pending codes on the computer?

 

Sometimes you have to reset those codes as well depending on the computer you use.

 

Sorry guys... Any answer Ive read here has already been done...

If no codes show, or pending, than what can be making the light turn on? Is it just on for no reason...?

 

May sound stupid, but a short in the panel can cause the bulb to illuminate.

 

Disconnecting the battery may not have done a complete reset. The AZ guys have only a basic code reader in my experience.

You may need to go to a place that has a better, more professional OBII reader to hard reset your computer.

 

I saw one post where this guy who really thought he new this **** was yelling, "touching the terminals won't do it, just disconnecting it a bit wont do it, 5 hrs minimum for "the capacitors to bleed off", 8 hrs is better" All with capitals and exclamation points. Anyway, it's one of those things that's not real tough to try.

(btw Firestorm, I caught my mistake the other day. Swapping the fuel pump really likely won't help make the starter go! Hope that didn't cause a hassle)

 

I guess Ill take up to the dealership and have them use their code scanner. Has anyone ever tried the "on off thing"? Supposedly you rapidly turn the key from on to off 5 times ending in the on position and any codes will pop up on the odometer..?????? I tried it with no success, maybe i did it wrong though...

 

scroll down to middle and try that......http://go.jeep-xj.info/HowtoECUcodes.htm