Hey everybody. I am new on this site, so please, be gentle,lol. I have a 1999 dodge dakota sport, with a 3.9 engine, and 4x4. My truck has 310000 km and I have pretty much done all my repairs myself. A few months ago my check engine light came on. I hooked up my obd2 scanner and got the 2 codes of p0138 02 sensor circuit high voltage (bank 1 sensor 2) and p0141 o2 sensor heater circuit malfunction (bank 1 sensor 2). This code is for the down stream O2 sensor ( after the cat). I bought the new sensor, replaced it and erased the codes. About 100 kms later, the check engine light came on again with the same codes. I did a bunch of other things to try to fix the problem, including, changing air filter, changing pcv valve, added some engine cleaner additive to the gas. I also traced the wiring harness to the o2 sensor and found that the 4 wires for the sensor were pinched uderneath a bracket, I was pretty sure I had found the problem.I removed the pinched wires and spliced in new wires and reset the codes. Once again after 100 kms the light came on. I really don't notice any difference to the truck's performance other than that I am not getting very good gas mileage as compared to before the problem. Another symptom that I have observed but not sure if it has anything to do with the problem is when the weather was colder the engine would turn over without started. I would have to press the gas pedal (not good for fuel injection) for it to start. When you did get it started it would spudder for a bit. After it was warmed up, it would run just fine. Could this problem have to do with the catalytic converter, or my pcm from the pinched wires? I am going to have to take my baby to a service center if I do not get this figured out. And that's why I am going to try this site as my last resort. Thanks and any help would be appreciated

 

Welcome to the site. I will move this thread to the second generation Dakota section,
FF

 

I had this problem on my 98!! It ended up being a broken wire in the downstream harness where it crosses over gas tank. I was able to undo a few clips and pull whole harness out the DRIVER'S side. I peeled back the plastic "snake" and out popped two wire ends. Spliced them together and problem solved. If I remember correctly it was the green thicker wire (automatic shutdown relay - Pin # 1?) It runs from the ECM to the sensor. Sorry I don't remember what pin on the ECM connection. I don't know why a broken wire raises the voltage to the ECM but it did because I was measuring it while trying to fix. Hope this helps.

 

Thanks guys for the quick responses. I am going to spend the time again to check my wiring to the sensor a bit closer. I had found the pinched wire before so I am going to check my original splice job I had done to make sure that it is still in good order. I am either going to find the problem or at the very least element the possibilty that it is the wiring harness. I will let you know how it goes after the inspection.

 

Dodge Caravan 2000 3.0 L engine, error code P0138.
P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)


What does this mean? How do I fix it! Thanks, Old Navyman

 

here is code 0138 out of the book. Leftbank Downstream or Downstream and Pre-Catalyst O2S shorted to voltage. which is oxygen sensor input voltage maintained above the normal operating range.
code 0141 is O2 1/2 heater circuit. Oxygen heating element circuit malfunction.

did you by chance change both O2 sensors?