2004 DC CEL P0136

Purchased this truck about a month ago, and previous owner replaced 02 sensors 2 weeks before listing it for sale. Driving home tonight and CEL comes on and this is the code it’s throwing. Quick research looks like it’s the 02 sensors giving a bad reading?

I disconnected both and re-connected and nothing. Any advice would be appreciated...I find it hard to believe something like this would go bad in a little over a month. Another forum suggested spraying the connection with electronics cleaner, haven’t tried that yet. From other research it looks like I am alright to drive on it for awhile, but I wanted it fixed soon so this damn CEL will go off.

 

Were they the correct denso sensors? Sometimes "off-brand" sensors don't "talk" to the computer correctly. Like being an English speaker your entire life, and trying to talk to someone who speaks penguin.

What engine? 4.7L or 3.4L?

 

I have the same question problem o2 sensors were replaced and I week later check engine come on..ending says 02 sensor bank 1is bad even though it was just replaced mine is 4.7 dc

 

2004 DC 2WD with the 4.7.

Another forum suggested disconnecting battery, disconnecting 02 sensors and cleaning them and then putting everything back together. I didn't have electrical cleaner, but I did that and now the CEL is off. I have a feeling I only put a "bandaid" on the problem. Got a feeling the CEL is going to come back on.

I don't know the brand, previous owner just said he replaced right before he listed it for sale. And the sensors do look brand new.

 

Time will tell. Guy might have changed the o2 thinking it was the problem and found out otherwise. Then he sold it to you and got away with it by disconnecting the battery for reset clearance. Now you are holding the bag.

How many miles on the OD?

 

Do not spray with electronics cleaner!

 

Could be the cat if the 02 sensor was already replaced with the correct one.

 

I just had cel P0057, P0420 and P0504 stored on my 2004 replaced the downstream 02 sensor and the check engine light went off. I’m hoping that’s it and not the cat. Time will tell.

 

115k

 

Would I potentially have to replace just the one cat from the side throwing the code? Or both?

 

Just the one should do it if that’s the problem.

 

Let me first say, that I do not like shotgunning parts at codes in general,...but, if this was mine, I would first determine if the O2 sensors are the correct OE or OEM (in this case Denso) parts. If they are, then you can start to look elsewhere. If they are not, personally, I would replace them with the correct Denso ones. It's not that much money....if it fixes it, great, if it doesn't, then it eliminates a couple of known possibly problematic parts from giving your future hassle

There are certain parts on a vehicle that I only like to use OE or OEM parts...this includes most things of an electronic nature. Good luck.

https://densoautoparts.com/find-my-part.aspx#searchResults

 

Thanks for sharing this, if I take one of the 02 sensors completely off would I be able to easily see if this is a Denso sensor or not?

 

Hard to tell from this pic, but I would think it would be written on there somewhere and since they are relatively new, still readable...

 

I would think so, I will take one off later and see if I can find anything. Assuming they are Denso and CEL comes back on (whenever that may be) would the next step be the Catalytic converter? Really hope it doesn’t come to this, just spent almost $1800 a few weeks ago on timing belt change and a handful of other routine maintenance it was due for.

 

Get all new Densos. My Fronts were replaced by others a few years back with Bosch. The Rears were Originals? and a multimeter test revealed ZERO resistance (way out of spec). Funny thing was no CEL Light.

Replaced with all new Densos ($45ish each). Buy 4 new Nuts from Toy for the Rears as they’ll be all gnarly. You’ll need a Thread Chaser for the fronts. Add some of that sweet Copper Anti Seize that comes with the o2 Fronts and run out the Crunchies from the threads.

 

Reached out to previous owner and he said he’s pretty sure these are the ones he installed. Looks like these aren’t Densos??


https://www.am-autoparts.com/year-m...2004&msclkid=df9c4e8dcf361dab69092e91b1c63fd1

 

Correct. Those are NOT Densos in your link.

 

Wheww, that is a bit of a relief for now then. If the CEL comes back on I’ll replace all 4 with densos and hope that takes care of the issue. Just replaced timing belt so my “truck maintenance” budget is running very thin currently.

 

The Denso Store has them for about $45 each for front and back. Hope it fixes your problem.

You can clean your Throttle Body and MAF, too. Need the proper cleaners. Cheap for $20 for both cans of cleaners. A new MAF Sensor cost is about $55 from Hitachi Store (OEM). Might be time.

 

What is the MAF?

 

Mass Air Flow Sensor. Mine was out of Spec. Replaced with new.

 

I have a K&N air intake (not by choice) but previous owner had it installed. Would this have anything to do with it?

 

It certainly could...duckduckgo "k&n maf O2 sensor"...