No CEL?!?!

[IrishBeatdown]

So I realize many of these problems in the newbie forum involve check engine lights that people get. I, however, have never thrown a check engine light in the three months I've driven this car. Crank position sensor horribly bad, no cel. Alternator gone bad, no cel. Pulling both o2 sensors than starting up the car just to intentionally throw a cel, no cel. It seems like there is some sort of issue here, I just want to be able to have my ecu function normally so I can OBD II diagnose because im no incredible mitsu tech. Anyone ever run into this before, I searched for no cel, but all I get is threads on CEL's.

 

[PuNkShoO]

No CEL on the dash or via OBDII? If you're referring to the dash, check to see that the bulb wasn't removed. Some people mod their cars, throw a CEL that cannot be easily fixed but doesn't hurt the car, and then just remove the bulb.

 

[cola]

You should read your posts out loud before you post them. From what I deciphered you want one of these-

Amazon.com: U380 OBDII Check Engine Auto Scanner Trouble Code Reader: Automotive

and put the bulb back in the CEL spot

 

[IrishBeatdown]

Sorry im an idiot, I forgot the most important part. The CEL light is operational, at least the bulb is, comes on at startup and shuts off. It just isn't getting tripped by things that should blatantly trip it. Is it possible that someone could chop the harness to keep the light from being triggered? The previous owner was a bit dishonest.

You should read your posts out loud before you post them. From what I deciphered you want one of these-

Amazon.com: U380 OBDII Check Engine Auto Scanner Trouble Code Reader: Automotive

and put the bulb back in the CEL spot

Yeah the post was a bit fragmented in retrospect, but im not worried about it. I have 2 OBD II readers and a 2.0 tactrix cable, I don't need help reading codes. The overriding purpose of the post as I specified is that I do not throw CEL's when I should obviously throw CELS and I suspect tampering. Just wanted to know if it was possible.

 

[IrishBeatdown]

Just wanted to clarify if someone ends up searching for this, the ECU was fried and wasn't throwing codes. I had to replace it.

 

[GSXTasy005]

I also think it's also worth mentioning for reference's sake, that OBD-II does not throw a CEL in your face the first time it notices a problem. If your ECU logs an "anomoly," it takes note of it, and goes on it's merry way. After the "anomoly" is noticed a few times, then the ECU will throw the CEL in your face.

Drive cycles are an essential part of setting trouble codes. If the OBD II system detects
a problem, it records a code and often will not immediately turn on the Check Engine
Light (CEL). Depending on if or how many times the problem occurs during the next
few drive cycles, the OBD II system will decide to erase the code or trigger the CEL.

source:http://www.alldata.com/products/downloads/ad_repair_drive_cycles.pdf

so you can't alway expect to hop in your car turn the key and immediatly know if something is wrong. The only way to MAKE your ECU throw a CEL (also known as a Malfunction Indicator Lamp (MIL)), is to go through the DSM-specific drive-cycles and wait for the ECU to find (or not find) a problem.

 

[IrishBeatdown]

I also think it's also worth mentioning for reference's sake, that OBD-II does not throw a CEL in your face the first time it notices a problem. If your ECU logs an "anomoly," it takes note of it, and goes on it's merry way. After the "anomoly" is noticed a few times, then the ECU will throw the CEL in your face.



source:http://www.alldata.com/products/downloads/ad_repair_drive_cycles.pdf

so you can't alway expect to hop in your car turn the key and immediatly know if something is wrong. The only way to MAKE your ECU throw a CEL (also known as a Malfunction Indicator Lamp (MIL)), is to go through the DSM-specific drive-cycles and wait for the ECU to find (or not find) a problem.

Good info there, I knew there was a period when the ECU is reset until it threw a code again, but didnt know of these cycles. I drove this car for hundreds of miles and got no CEL's, then replaced the ECU, and within 5 miles or so it popped the CEL's. Still not sure what went wrong.