Contour Enthusiasts Group Archives Forums General Troubleshooting I'm confused with regards to KOEO versus KOER??

With my sisters 95 Contour, all I've ever done to check the PCM for codes is jumper the two connectors, and turn the key to the ON position. Then just wait for the Hard and Memory Codes.

I have never attempted the KOER tests because it seems confusing. Plus, being so used to GM cars with no KOER test, I don't understand how or why a KOER test might show a code but a KOEO check would not??

I mean, wouldn't a fault when the engine is running automatically become a Memory Code? And therefore be checked by doing the KOEO check?

I'm just wondering if it's really possible to get a code during a KOER test but NOT a KOEO test? It seems strange if that's the case...

THANKS AGAIN!:)

PS Has anyone here ever discovered a problem by doing that "Wiggle Test" thing??

KOEO - if I remember correctly, checks various sensors, etc. through a diagnostic procedure that begins vs KOER where a sensor could cause problems while the engine is running, etc.

The KOER is a dynamic test. It steps through various functions with the engine running and checks engine performance/sensor function.

If you look at the list of possible error codes, you will see that many are distinguished as either continuous/memory, EO (Engine off), or ER (Engine Running).

There are plenty of codes that will only be generated during the ER test.

Steve