I did a search, and in one of the limp mode threads, somebody said that the o2 sensor can cause it... Anyway, i pulled codes today on my 87 n/a and it gave me code 5 - no signal to ecu from O2 sensor. Before I go and get a new one, I want to confirm that a faulty O2 sensor can cause limp mode.

Also, can I clean the O2 sensor to fix it on my own?

Also, can the COLD weather affect the sensor (would a new one would work better in the 20 degree weather i'm constanly in)?

Last, if I do in fact need a new one, should i get the one that victoria british sells, or is there a better one from napa or something?

any help would be most benificial cause when i am driving along and all of a sudden my car falls into limp mode, it can be a bit scary... almost got rear ended :-/

Thanks
(sorry if these questions sound stupid, I'm still in the learning process of cars in general, esp. our 7's!)

 

AFAIK S4's don't have limp home mode.

Santiago

 

ugh, well, it has all the symptoms of limp mode... like, i can't get the engine above 2000, it's like it's hitting a limiter

 

Having an error with the O2 sensor sensor code will not trigger limp home mode.

If the O2 sensor wire signal lead gets shorted to ground, it *can* blow circuits inside the ECU, which can cause all kinds of headaches.



-Ted

 

do the s4's even have a limp home?

 

I guess technically it doesn't.
I call "limp home" anything that prevents the car from running normally, so to me yanking the AFM is "limp home mode".

What about the TPS?


-Ted

 

yeah, lol works for me. how about buck home mode?

 

no, they do not have limp mode, only s5's do. The culprit in my particular problem (which is in my post "can't get engine over 2000") was a lose connection between my tps and ecu (at the tps end), so i tightened up the wires, and it's been running just fine (although i probably should get a new o2 sensor for better mpg and such)

Once again thanks everybody for your help!

 

Good luck changing the O2 sensor. I just bought one of those deep socket tools. Wednesday I destroyed my hands, fingers and arms in the rain as I unsuccesfully tried to remove mine, hopefully it will be much easier now w/ that tool.

 

You sure?

The O2 senor signal goes through a 10K ohm resistor before it hits any IC's in my schematics.

I'm not saying you're wrong here. If there's actually a case of this happening it might be helpful in figuring out what IC450 is.

Seems like grounding that wire might fry the sensor, but not the ECU.

http://www.mr2.com/TEXT/O2_Sensor.html