Dodge Dakota o2 sensor issue.

[Tyler]

I bought a 2001 Dodge Dakota SLT about 2 weeks ago, when I got it it was showing 4 codes, 2 for evap emissions leaks, 1 for a cylinder 3 misfire, and 1 for the bank 2 sensor 2 heater malfunction.

well, I got the misfire, evap, and bank 2 sensor 2 heater fixed.

in order to fix the bank 2 sensor 2, I replaced the sensor with an OE denso unit, while removing the old o2 sensor, I snapped it off in the threads. so I took the truck to a local exhaust shop to see if they could do anything, they couldn’t get the old sensor out either, so they welded that bung shut, and cut/welded a new bung about an inch or 2 below it.
cleared all the codes and was good to go.

About 2 hours later as I’m going thru an intersection, the truck lost all its power for a second and the CHECK ENGINE light came back on. so I pulled the codes, and this time its bringing up P0051 bank 2 sensor 1 heater circuit low, and P0152 bank 2 sensor 1 shorted to voltage/voltage high.

I’ve done a visual inspection of the wiring harness, no visible damage, no burns from the exhaust shop, and no fluid leaks around the wiring. it all looks to be in great shape.

My question is, does it sound like the sensor just went out? it just seems kind of weird to me that I had no issues with that sensor til I fixed the sensor 2 in that bank, then a couple hours later boom, now this sensors acting up.

I’m not too well versed in obd2 vehicles, so I don’t have a ton of knowledge how the sensors interact and work together, is it possible that replacing the bank 2 sensor 2 with a brand new sensor may have made the ecu realize bank 2 sensor 1 was lazy or something?

what do you folks think? more investigation needed? or just go ahead and replace that sensor?

oh, the truck is an 2001 Dakota slt quad cab 2wd with 4.7 automatic, and the mileage is 215xxx, thanks.

Topic

[EricTheCarGuy]

I wouldn’t be so quick to condemn the sensor just yet. It could be a wiring or connector issue. I cover those contingencies in this video.

Good luck and keep us posted.

[Tyler]

Thanks!
I’ll have to check the heater resistance with my DVOM, if that’s bad I’ll just replace the sensor.
When you said in the video about the external holes on the o2 sensor, it got me thinking, would PB blaster getting on/in there cause an issue? when I was attempting to break the bank 2 sensor 2 loose, I sprayed some PB blaster up and I over sprayed a good bit on the one attempt due to the tight spaces. enough to hit the block lol

Also, if the resistance in the heater circuit is good, how would I go about testing the o2 sensor itself or testing the continuity to the PCM or just the wiring in general? I have a decent DVOM, but no access to a scanner with the ability to monitor o2 sensors in action, and the cheapest shop around wants $50 minimum to do a reading/diagnostic, which in that case, I would rather just replace the sensor for $45, and see if that fixes it.

[Tyler]

well, I tested the o2 sensor heater just now and it showed nothing on the multimeter, no high resistance, no low resistance. absolutely nothing. so I’m thinking I’m looking at replacing the sensor.

[EricTheCarGuy]

If it showed an open circuit then then heater has likely failed. The easiest way to check O2 sensor operation is to view the live data on a scan tool. That will verify the sensor, the wiring, the connectors, and what the PCM is seeing. Yes, if you get PB blaster in the holes in the O2 it can damage it.

Let us know if the sensor fixes the issue.

[Tyler]

Right on.
yeah, with no access to a good scan tool with live data capabilities, and seeing a dead short in the heater circuit, I’m fairly certain that the sensor either just gave out, or I got PB blast into it and fried it.

I ordered the sensor this afternoon, I’ll have it in the morning, was able to score a deal for an OE unit at $34 so that’s even better lol

with my work schedule, I’m probably not going to have a chance to really work on the truck anymore til Monday or Tuesday, but as soon as I get it changed out, I’ll post up my results and, fingers crossed, wont be seeing a check engine light or 7.5 mpg anymore haha.

I do have a question relating to the CHECK ENGINE light and codes, what would be the best way to clear the codes without a scanner? I’m hesitant about disconnecting the battery and resetting the PCM because I don’t want it to have to relearn everything, is there a way to just clear the codes without a scan tool?

And thanks a bunch Eric, your videos and expertise have been a huge help in my automotive work, and a great learning experience that I’ve been able to use many times now.

[Stephen Bowen]

Normally once you correct the issue that triggered the CEL light to come on? After a set number of key turns (aka, a set amount of starts-drives-shut off’s) If the issue does not repeat–the code will self clear. It’ll probably stay in memory if the system maintains “History” codes…but it should turn the light off and that’s that.

S-

[Tyler]

ok, ill have to see how this particular PCM handles all that, I know dodges are kind of weird with electrics lol

as long as it clears the light, and allows the computer to go back into closed loop and get some gas mileage back, I’ll be ecstatic.. lol

[Stephen Bowen]

You want oddball electrics in a car? Wife’s new beetle. I had to relearn most of my older training just to service it.

Don’t be surprised if it can take upwards of about a week…maybe 100-150 miles before it resets itself. Sometimes it’s just how the guys in the computer lab’s programmed it.

Just keep an eye on it, and you should be fine.

S-

[Tyler]

most of those german cars are a PITA to work on.. lol

I was working at a local shop and we were doing something to a newer jetta or something.. that thing gave us hell for about 3 days. finally got the sucker fixed and the lady that owned called to say she blew the engine about a week later and traded it in lol

[Tyler]

Well, picked up the sensor this morning, and was able to change it out at work after I clocked off. started the truck 2 times and the CEL is out, trucks running and idling much smoother. now I just have to let the PCM figure everything out and adjust the fuel trims.

hopefully, this, coupled with a couple other things I have planned for this coming Friday will get some gas mileage back in this hog, but right now she’s at least running heaps better.

Thank you guys for your insight and suggestions, definitely saved me a good bit of cash getting it done DIY versus going thru the stealership or garages haha.

[Author]

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