self test mode (koeo and keor) starts on its own?

[rockin_rick]

Since I've installed the TwEECer, my car will most times enter KOEO on it's own once the ignition is turned to on. The fan will run low, then high, then off. The pump also runs for a sec, then off. Then codes start flashing. I even had it enter KOER on its own after starting the car.

I've checked the wiring and the STI input is not jumpered. I used a multimeter to measure the resistance between the STI input and ground. It was about 4K ohms. I then removed the ECM and measured again, and it was infinity (no short).

Has anyone ever heard of this / had it happen?

Would someone PLEASE measure the resistance between the STI input and ground with the car and ignition off? It shouldn't take but a minute. The STI input is the connector with only 1 wire in it where you jumper it to the other 6 pin connector when you want to start a KOEO test.

Thanks,
Rick

 

[mo_dingo]

To trigger KOEO/KOER codes, the STI input needs to be shorted to the SIG RTN, not ground. Unless the SIG RTN is a ground, idk though.

http://www.allfordmustangs.com/Detailed/445.shtml

Using STI as positive, and the battery terminal ground, engine off & acc. off, I get no reading at all. If I hook up positive to SIG RTN and ground to battery terminal ground, I get 2.7 ohms.

Scott

 

[rockin_rick]

Thanks for the info Scott. SIG RTN is connected internally in the ECM to ground. It's the ECM's ground reference for all the sensors. That's why SIG RTN to ground gave you such a low reading.

So you are saying that the resistance between STI and the battery ground was no reading (infinity AKA open circuit)? That's way different than my 4K ohms reading.... I wonder if my ECM is damaged?

Rick