ASOG Forums

code 21: o2 sensor grounded.
code 32: EGR failure

and it only happens when im sitting at stoplights, and generally when its cold.

i suspect a bad connection somewhere but i can't find it. i have a wiring diagram and there is a connector where the o2 sensor signal wire is sitting right under(or over, i cant remember) the EGR signal wire. and its a J/C 3 on the diagram and it says its under the eng. compt. relay. but i can't find the connector, i suspect its hidden in the firewall somewhere, but the short could be anywhere where those two wires touch.

anyway would you guys support my hypothosis or do you have any other suggestions before i start tearing apart(carefully, of course) wireing bundles trying to find the short. the main reason i think its a short somewhere is how specific the engine code is to say "o2 sensor short"

oh and just for anyone who's wondering i go to school for automotive service/managment, and thats where i got the wireing diagram and the meaning of the codes. its a handy resource!!!

any ideas? anyone?

Well the code 21 can mean a bunch of things, all related to the O2 sensor.  I would just replace it.  The EGR doesn't affect engine performance, if it really bothers you to have Check engine light on you can pull off the EGR sensor and clean it.  That's usually what sets off the code.

well the engine light isnt what bothers me, its the fact that it comes on at all, that bothers me, because other than this my car is (mechanically speaking) currently perfect(knock on wood), but since everything is pretty much mechanically sound is one of the reasons i suspect a wire has been exposed somewhere, so im not going to jump to replacing the o2 sensor just yet, considering i don't know which o2 sensor im looking at i'd have to replace both. but i will take the suggestion into consideration after i have gone over the wires.

as to the code 21 alldata(online automotive resource for the uninformed) says "o2 sensor short" and it has separate codes for o2 sensor failure. but thats alldata, it could be wrong. but again it points to a short.

i would much rather trace the wires and be wrong, than replace the o2 sensors and be wrong, ya know?

it doesnt bother me THAT much, but it is a concern, and it hasnt happened since i posted originally, so no new info on that. im not on a crusade to fix this tomorrow or anything, but ideas are always welcome for when i do go to fix this, currently i just don't have the time to do anything other than basic maintenace(i actually don't really have time for that, but i make time, cutting back on sleep and whatnot).

Take the care to AutoZone and get it scanned for free it will tell you which O2 it is and it will give you a better idea.  The O2 is only like 20 bucks or something.  I've seen many O2 codes and it's usually just an O2 that died.  It's like plugs and wires, eventually they go.

Possibly a bad wire, yes, but not likely.

Good luck on finding the fix.

eh, we have better scan tools at school, and the people there know more :P

there are 2 O2 sensors. There is one before the cat and one after the cat.

For Code 34, check the pipe before you replace the egr. Mine was cracked and causing a leak. I finally realized it after having my car for 4 years.

oh yeah, thanks, i didnt even think of looking at that.

Also you can check the little plastic vacuum line that goes from the intake to the EGR solenoid.  That breaks pretty easy after it gets old and could cause similar problems.  Are you having any driveability issues or just the light and the code?

besides the small drop in gas mileage that i blame on uneven tires and cold damned weather, its just the light and code....and it only happens about once every 2 months, and i just unplug the PCM before i go to class and plug it back in after im done

im waiting for some theif to try to steal my car on a day my CEL came on...tee hee...

once every 2 months??  I would attribute that to a loose wire somewhere... hmm hard to say.

thats what i thought, only happens at warm idle, when my engine vibrates the most.

but yeah, if i had the time i'd just replace the EGR and the o2 to figure out if its the sensors or wires. i think they need replaces soon anyway(esp my o2s). when i get the time im planning on doing a full tune-up, the o2, plugs, wires, teh werks.

www.disturbingmotorsports.com is a great place to get all the things you need for a full tune-up