ok well in case no1 read my last post about limp mode, here i go. I took my car out for a spin since it was sitting for a while, well, i was driving around for a while and i decided to "open her up". my car right then at about 6K went into limp mode while flooring it. I got several codes - 27 (OMP), 33, whatever the CAS code is and a code 11 (air intake Temp sensor) and some other ones that i dont remember. O and just to add to the story, my alt is dying and my battery is pretty much dead. Well i drove it around the other day and guess what, it drove normal. I did drive it a little hard but she ran like nothing was wrong, the only code i was pulling was code 11 (air temp sensor) and(im also running a little premix). Is it possible that it went into limp mode because the alternator wasnt providing the car with enough power, like the ECU wasnt getting enough power so it put itself into limp mode?? -alex

 

very possible, but limp mode can be caused by other things. such as overheating.

 

My check engine light would come on, and the car would go into limp mode. I was unable to pull a code, however.

I would turn off the car, let it sit for a minute, start it back up and it would run fine for a period of time before going back to limp mode.

Sometimes I would take a short trip and it worked fine, no matter how hard a drove it.

I finally got it to pull Code 27, replaced my OMP and it's been fine since.

 

will not exhaust overheat sensor/switch turn ECU into LIMP mode?

 

The cable from the positive battery terminal to the starter was pretty badly corroded on the starter end in my '90 GTU. The resulting short caused limp mode with code 01 "trailing coil/igniter." I replaced the wire and now it has been running perfectly for three weeks or so. I think there are several possible reasons for limp mode, obviously one is electrical.

 

well what im saying is that is it possible for the ECU to go into limp mode do to a lack of electrical power needed for it to fully function?

 

yes, very possible, and very likely

 

think about it...if the ECU's not getting the input voltage it needs, how can it supply the proper ref. voltage to the sensors? And if the sensors are not getting a good input voltage to work with, how are they gonna send a good signal (in parameters) back to the ECU? VIOLA, codes pop up...(my theory, anyway, I don't know if the ECU's reference signal voltage is directly proportional to input voltage or not...)