The return of the CEL..

[pat julian]

Having corrected the EGR code with a new EGR valve,. all was good for about three weeks...then the CEL comes back on after driving about five minutes...It will turn off every time the engine is stopped..only to flash back after five minutes of driving. Took it to O reilly's to run the OBD1 scanner..but the test results said "pass'..this was with KOEO..and the CEL was off as well..I finally realized to pull the code apparently the OBD1 scanner must read the code KOER with the CEL on...would this be correct ?? can you pull a code with the engine running ?? It's a '93 2.3 five speed..152K ..No dpfe sensor on the 2.3 that year...Thanks...

 

[RonD]

Good read here on OBD I codes/tests

http://www.therangerstation.com/tech_library/OBD_I.shtml

 

[adsm08]

Ok, there are three types of codes. KOEO, KOER and CMDTC.

KOEO is Key on-Engine off, these are generally hard-fault circuit codes.

KOER is Key on-Engine running, these codes tend to be related to erratic or out of range signals, but anything that shows up KOEO will also show up KOER.

CMDTC is a Continuous Memory Diagnostic Trouble Code. It is a fault that may or may not be present right this moment, but has been present long enough to set a code either since the last code clearing or in the last 40 key cycles.

Since you cannot initiate an OBDI self test if the key is on before the scanner tells you to turn it on running codes with the engine already running is out. You need to scan for memory codes.

 

[Mazda]

Pat: get one of these. will pay for itself first time you use it.

http://www.amazon.com/INNOVA-3145-Ford-Digital-Reader/dp/B000EW0KHW/?tag=959media-20