First off thanks for the help on my last problem.....EVAP fixed.

Of coarse a new one popped up. Truck has been running fine for the month I've owned it till yesterday morning. 5.9L gas. She didn't want to start. It was 26 degrees. Well it ran fine after warming up. Threw 2 codes. P0037 and P0138. Again this morning it started hard. About 5 turnovers and playing with the pedal.

Here is where I am at. I checked the Plenum visually, no pooling oil. I'm gonna get a magnet and see if it was changed. I let the engine cool completely, pulled the negative, unplugged the pre cat O2 , cleared the CEL and she fired right up as usual. No visual wire issues with the post cat O2.

Id figure Id post it up as I cant find any search answers on what the problem is if the pre O2 out makes it start better.

Again this just popped up, and the truck ran fine after the hard start and 1-2 mins of warm up. I'm gonna let it cool again and plug the O2 back in and see what happens. I've still yet to check the #8 plug also. Thanks for any help.

 

P0037 is o2 heater low, maybe a blown fuse.
http://engine-codes.com/p0037_dodge.html

P0138 is o2 heater high.
http://engine-codes.com/p0138_dodge.html

check fuses, clear codes, reconnect, retry.
if it comes back, replace O2.

 

OK..... What fuse would I be checking? For the 0037? I cant find fuses in the manual. I assume this has nothing to do with the hard starting?

As for 0138, I'm assuming that the rear O2 is "downstream" O2 sensor if I get one from Advanced? They have a few instock(NKG) and want to order online for a coupon code but need the right one. Thanks.

 

Cleared codes plugged the pre cat O2 back in..... it fired right up but threw code 0037 again. I thought 0037 had to do with O2 sensor also, not the heater element???? None of the fuses make sense for the heater element? I checked the O2 sensor fuse under the hood and its fine.

 

fuses are in the pdc box, next to the battery. it think its labeled as O2 or oxygen sensor. heater element is inside the O2 sensor. the 2 white wires feed them. you can verify 12volts on those white wires with key on. edit - it might be a relay in the pdc instead of a fuse...

before replacing O2, unplug your old and check the shape of the plug, round vs square so you get the right one. shop online for better deals advance has some good online discount codes.

 

OK I'm starting to follow along.....I hate electrical. Thats the fuse I checked, 20 amp and its fine. Both my O2's are square plug. Should I change both? Before and after cat? Advanced has them as upstream and downstream. I assume upstream is before the cat? Also federal and california. Truck was original in NY. Has left and right also(same part), but my exhaust is 2 to 1.

As stated before it fired with the before cat O2 unplugged, fired right up, no code thrown. Plugged the before cat O2 back in and threw the 0037 code back up. I haven't driven it yet, just ran in driveway. Negative was disconnected when plugging/unplugging O2 sensor.

So I have to "*** u me" the 0037 is the before cat O2, and the 0138 is the after cat O2? Should I just replace both or which one? Im gonna get a magnet also to check the plenum. Shes got to go back to work on Monday so thanks for the help.

 

Go get the pre and post 02 sensors and replace them. I am not going to recommend any brand of 02's to get as I have had nothing but problems with the brand you will be told to get.

 

Enlighten me . Just read old posts that suggested NOT Bosch....which seems weird......Bosch has quality stuff, but Ive never changed any O2 sensors. And its my 1st Dodge just 1 month in.

 

supposedly, the rear(downstream) O2 has no bearing on how the engine runs, and its only purpose is to verify that the cat is working properly to reduce emissions. the rear O2 is referred to as "sensor 2" or "bank 1, sensor 2".

accordingly the front (upstream) O2 is referred to as "sensor 1" or "bank 1, sensor 1". its job is to provide feedback to the pcm, and under all the right conditions, provide the emissions information that allows the pcm to adjust the fuel trim between rich/lean.

so in theory - the rear o2 has nothing to do with how it runs, and the front o2 should affect how it runs only in closed loop, which is whens its all warmed up. but- you're not the first to experience otherwise, so who knows what the pcm is actually thinking.

also the odd thing is that internet says both these codes are related to the rear O2, not the front. are you sure you're unplugging the front?

if money is no issue and your o2's are over 60-75K miles old, they are due for replacement. if money is tight, you might focus on the front, and maybe leave the rear unplugged and see if the light stays off. i'd think the cel would come back on if its unplugged.

here's a better explanation.
0037 rear o2, voltage low. http://www.obd-codes.com/p0037
0138 rear o2, voltage high. http://www.obd-codes.com/p0138

 

Oh its the front I unplugged. Its on top of the tranny and hard to get at. My rear just hangs and is easy access almost touching the skid plate..... Probably routed wrong. I'll probably zip tie it up. This truck was probably owned by some backyard mechanics(I am also, just not that bad), as the gas tank straps were ratchet straps. GREAT idea, lets use $10 in ratchet straps instead of $30 oems???? Harder gettin the straps out then puttin real ones in .

Anyway I'm gonna change both of them , shes at 99,990 and shes gotta be good or I cant make money myself. NOW which brand?