I am a new member and am hoping someone can help provide some information that is proving difficult to find on my own. I am currently trying to troubleshoot a p0135 (front O2 heater malfunction) in a recently purchased 2002 Durango with the 4.7 and 4x4. The car currently runs well and has no smoke from the exhaust( it does have a sharp smell from the exhaust, not converter but maybe rich)
When I bought it the entire instrument cluster didn't work, no gauges, no odometer( i believe it has 250,000) no warning lights, nothing. Long story short after repairing some grounds, checking for sensor shorts, and even replacing the pcm with a used one it turns out the issue was a bad instrument cluster. I put in a new one(used one from a 2002) and replaced the original pcm.The original is back in the car now. The pcm has 4 equal sized plugs. I am told this is the NGC or Next Gen Controller. After the instrument cluster started working the bell and light for the abs would constantly flash and ding until I took it to the dealer to have the abs module reset. That's what they told me they did anyway. Whatever they did it worked and I had a clear dash with no warning indicators for about 20 minutes. I got a p0171 (left bank lean) indicator. I cleared the code and it came back so hoping to get lucky I installed a new NTK O2 sensor. I drove it about 40 miles to work with no indicator but when I started it to go home the check engine light was on again. I was surprised to find the code was a p0135.
This is where things get fuzzy. I tried to get a service or shop manual to troubleshoot this issue. I downloaded 2 ( including one from this site, thank you) but both are the same and I don't believe my application is included in the wiring diagrams. The manuals only show diagrams for vehicles with the 4.7 engine and the jtec pcm or with the 5.9 engine. I did check the locations in the power distribution center under the hood for the locations listed in the print for the power source to the sensor but the wires were different.
Backing up a little I did check the pins in receptacle that the front sensor plugs into for the proper voltage. I don't even know if the expected numbers are right because I don't have a diagram with the proper voltage and pinout for that plug with the NGC pcm. What I got was pin 1- approx 4 volts dc, pin2- ground, pin 3 approx 1 volt dc, pin 4 approx 2.5 volts dc. I want to assume that I am supposed to get 12 volts dc to pin one but again I am not sure. I don't know where the source originates from and it's difficult to check its path inside the wiring harness. Again I am not even sure what the expected voltage should be. I'd be ok with replacing the wire if necessary.
I believe the pin one wire is brown with an orange stripe
fyi I believe this is a Federal emissions or non California emissions vehicle.
I did go to a dealer and even offered to pay for the right information for my vehicle but the one guy who I was told could probably help me (service manager) wouldn't even talk to me. I went back a second day when he was out the first time I stopped by and he told the service writer I spoke to that If I didn't bring in the vehicle so he could troubleshoot it himself then he couldn't help me. Oh and by the way the prints are proprietary and I can't see them. This by the way is a different dealer than the first one I took it to. (I don't have a problem with the other one but this one is more on my way home from work.) Anyway I'm tired of going to dealers.
Any information that can assist me in resolving this issue would be appreciated.
Thanks, Mark

 

Should see 12 volts on the heater circuit. Usually, there is a relay in the PDC under the hood for those...... May even be a fuse.... Not 100% on that.

The mechanic wants you to bring the truck in, because he gets paid to work on them. He doesn't get paid to tell you how to fix it.

 

There is not a relay or a fuse in the pdc, believe me I checked. There is a place where a relay would be if it was equipped with one but the metal connectors aren't there under the space where you would plug the relay in. Putting a relay in this position in my fuse block would do nothing. I also opened up the pdc looking for the wire I found at the sensor connector and no such wire was anywhere in the pdc. I suspect in my application the wire may originate in the pcm. I did find a wire with the right colors going to one of the connectors but so far I am hoping I won't have to open the wiring harness all the way back to see if its the right one.
Regarding the mechanic not getting paid to " tell me how to fix it", I wasn't looking for anything but a print with pertinent information to my application. I also expressly stated several times that I would pay.

 

Yeah, wiring diagrams would sure make this exercise easier..... Some dealers are pretty free and easy about letting folks peruse the manuals, copy pages, etc, others.... not so much. You can likely find a service manual in PDF format on the web, from various sources, for 20 bucks or so, and that would have the diagrams in it. May also have a troubleshooting table to help you along. On these computer controlled vehicles, an accurate wiring diagram is pretty much a requirement. And there is a host of other useful info in the service manual as well.

 

No go on the dealer. I tried the the dealer that took care of the successful ABS reboot and the service advisor wouldn't have any part of even discussing the idea with a service tech. without me bringing it in again. Since the info isn't in any of the service manuals I've gotten already I decided to see if there was some type of supplemental manual for my application. I turns out it appears there is. I couldn't find any free downloads so I ordered a hard copy from ebay. (2002 powertrain diagnostic proceedures durango NGC supplement) It's going to take a week to get but I'll post if it has any helpful info when I get it.

 

the 2002 service manual on this site includes the NGC wiring (at least everything i have ever needed from it when i had mine). however alot of it was the same between the jtec and NGC, so if there is no reference to which one then the wires were the same.

check the manual you have for the NGC pinouts, if they are there then so is the rest of the relevant wiring.


EDIT: check page 8w-80-70 for NGC connector C4,
also page 981/2141 in the PDF that i have.

upstream (pre-cat) oxygen sensor is on page 8W-80-57 (968/2141) and lists pinouts for NGC and JTEC PCMS in one table)

sensor supply is typically ~5v and heater voltage would likely be ~12v, but i havent had time to confirm that.