My son called me about a fault code on his 2000 Dak 4x4 w/V6, manual trans. He said the code is P0138. Looking at allpar.com, the code says HO2S Circuit High Voltage Bank 1 Sensor 2. Can anyone tell me what this means and where this sensor is located, if it needs replacing? Does he need to take this to a shop or can he do it himself? Thanx.
Larry
This is the post-cat oxygen sensor (little thing sort-of looks like a spark plug sticking out of the exhaust pipe, behind the catalytic converter, with a wiring harness coming out of it), and since the computer thinks the voltage is high all the time, it could be one of two things (most commonly). Either it's a melted/shorted wire, as the wiring harness runs right next to the exhaust, and if any of the hangers/tie-wraps come loose, the wiring could come in contact with the exhaust.
If the wiring all checks out, then you've most likely got a bad oxygen sensor. Replacement is fairly straight-forward... you disconnect the electrical connection about 12" back from the sensor itself (the sensor has a pigtail), and unscrew it. That's the tricky part. You either need an oxygen sensor socket (like a really deep socket, but with a slot cut in it to allow for the wire pigtail), or a wrench (flare-nut is best, box-end is second choice, open-end as a last resort). It's going to be TIGHT. Use some penetrating oil on it first (Kroil, PB Blaster, or the like... WD-40 won't cut it). On my friend's Durango, the orientation of the O2 sensor was such that we had to get really creative with our wrench placement, and use of cheater pipes.
The sensor will run somewhere around $50-$80, and can be had at most auto parts places.
Thank you, Tom. I will pass this along to him and have him let me know what he finds and I'll post results.
Larry
Also, make sure that they give him the correct sensor. The post sensor is different than the pre sensors and even though they will interchange in mounting positions, they will not plug in to each others connection. Don't ask me how I know this. The best idea is to closely compare the connector and wire length with the old one before you even leave the store (IOW, take the old one out before you even go) . I believe that they are color coded at the connector and the post unit has a cage over the tip and pay close attention to the key in the connector as it is in a different position on the post and pre sensors otherwise you will be making multiple trips.
Thanx for the additional info. I sent it on to my son. Haven't heard from him, yet.
Larry Behold Beware Believe
: > Larry : >
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