Hey guys,

My dak is intermittently popping Code 21... I don't mind spending a bit of time and money to just replace the sensor, because I think it's a pretty old sensor. I am going to use an NTK sensor because it is OEM.

-How do I know whether or not I need an 18" or 34" sensor harness length?

-Where exactly does the sensor harness connect with the truck harness? The wiring seems to get lost somewhere above the bell housing and below the firewall...

-This is not a rich or a lean code, but essentially a bad signal code, right? Could there be any other cause than a sensor or the wiring?

-How do I get a torque wrench and crowfoot O2S tool onto the O2S? I have the special crowfoot, do I need to get at it from below with a drive extension?

I might also add that the engine was swapped in by a mechanic friend and the downpipe might have been modified. The wiring harness certainly may have been hacked up as well, because it was a swapped out engine.

(To paint a complete picture, I might also add that the truck is currently a bit slow to fire up... The starter cranks just fine, but the engine is slow to wake up and fire. I am thinking that this might be a new fuel filter or pump issue, but if it is related to the O2S, I wanna know... Don't think it is because all the start-up modes are open loop control modes)

Thanks for your consideration!
DBB

 

Just follow the wiring till you feel the plug. I needed help from a friend to get it, the plug seems to be on top of the tranny a bit closer to the driver side. I had him hold the plug open and I tugged the wire till it popped loose. As for removing it I used a box wrench that I cut the other side off of so i could slip a cheater bar on it.

 

Not sure on the length. I got one with 18" I believe. Still had some slack to it. Idk if yours is 2wd or auto like mines is though or if that makes any difference.

 

Yeah, I'm a 2WD with an automatic, so I suppose it's safe to buy the 18" leads then.

the box wrench with cheater bar sounds good, but what about the reinstallation? How to torque to 22 ft-lbs with the crowfoot O2S tool?

Thanks for your help.

Folks: Any opinions on the slow-to-light-off condition, or other possible reasons for the Code 21?

 

Use an 22mm or 7/8 open end wrench and tighten. You don't need to use a torque wrench.

 

when i got one for my 90 2WD auto, i just went to the dealer and got one when i got home it was too short went back and they said "oh, you need the longer one" !!!!