Ok, I've got the service manual on my Dakota... and I've read up on the O2 sensors. As I am throwing a P0138 (M) 1/2 O2 Sensor Shorted To Voltage Oxygen sensor input voltage maintained above normal operating range.

I've got the California Emissions system with the 4 O2 sensors.

From sitting in the driver's seat, facing forward, which side is it on. Also, is it before or after the catalytic converter (I am assuming it since it is downstream, that it is after the cat.)

I've looked at all of the wires (all 4 to each sensor) and found nothing to be wrong. I've done no mods or altercations to the truck. These are factory (stock) oxygen sensors.

All I want to know is where that 1/2 O2 sensor is in relation to me sitting in the driver's seat with information on if it is before or after the cat.

Thanks.

 

how many miles do you have on your truck?

1/2 = bank 1 sensor 2 (its on the driver side, after the mini cat) downstream
1/1 = bank 1 sensor 1 (driver side before mini cat) upstream

2/1 = bank2 sensor 1 (passanger side before mini cat) upstream
2/2 = bank2 sensor 2 (passanger side after mini cat) downstream

if you are close to 60k or + miles and you have stock o2s i suggest replacing all of them. they are about 50$ each.

 

Thanks for the info. I've got 12,674 currently.

So I went under the engine, and I found the o2 sensor that was giving the error and I replaced it. It didn't look too bad... but I noticed a lot of rust on the sensor itself. I guess it just happens from the heating and cooling. With only 12k on the clock... that's pretty bad. Then again, it's a 2000... that was in there for 7 years.

Who knows... maybe even a faulty sensor. But I reset the code and I took it out on 2 cold starts and 1 warm start, with a mix of highway and slow speed driving and no CEL. I notice that it also idles smoother.

I'm glad that it is fixed, and the fix was easy... phew!

Soon it will be time for storage... I'm going to miss it this winter... But next summer it will be a blast to drive.