P0440 + P0136

Hey all,

Is there any possibility these two codes go with one another? I know the 440 is Evap, and the 136 is downstream, but I read the 440 is usually accompanied by another code. Exhaust is new passed the headers. Bank 2 sensor is new. No exhaust leak.

Thanks

 

Seems like 95% of the time the 440 is just a loose gas cap. After looking them up, I don't really see how the two codes would be related.

 

Also seems like the 440 is always concurrent with 441, 442 or 446.

 

I had p0440 and a p0446 code pop up. For mine I ended up replacing the overflow check valve and the gasket that goes with it, OEM gas cap, charcoal canister, filler neck, and hoses.... Moral of the story, bite the bullet and get it smoke tested... but do that after you tighten your gas cap and reset the codes.
*** also make sure your hoses are clamped and tight

 

I found a couple hose clamps that were rusted to dust. Pinched them, and they crumbled.
Today’s efforts included a new gas cap, replacing the clamps and resetting the codes. I think the 0136 may have actually went away. I took the truck to a shop and they leak tested the exhaust. No leaks. Smoke test is next if the issue returns.

 

Just sold my ‘12 tacoma and bought this ‘02. I didn’t realize I’d be playing the CEL game right away.

 

I doubt those 2 codes are linked. I had the P0136 code last year, a new rear Denso O2 sensor fixed it.

Only use Denso brand sensors on these trucks, anything else will likely not get rid of the code or make it come back shortly after.

 

Used Denso from Rock Auto.

 

Hmm, I wonder if maybe the seal/gasket isn't completely sealed on it? For a new Denso sensor to be throwing that same code, there's gotta be an issue either with the install or maybe it was a bad sensor to begin with...unlikely but possible.

 

No leaks in the exhaust was verified by a muffler shop today. Possibly a bad sensor, but the “rich” smell is gone, and my MPG’s are great compared to what they were. Hopefully I’m just dealing with the 0440 code, and the 0136 is gone. Fingers crossed that today’s minor efforts resolved the 0440 as well. I’m not usually that lucky though.

 

Oh you haven't cleared the codes since you installed the new sensor? If you haven't then the ECU probably hasn't completed a full emissions cycle yet, once it does then it will erase the codes on it's own. That can take up to a few hundred miles though, usually after I do a fix I'll clear the codes myself with my code scanner (or disconnect the battery for a few minutes). That will clear the check engine light, and if the issue is still there then it will come back...if not then it will stay gone.

It's not very common for a check engine light to clear itself instantly after fixing an issue, depending on what the issue was. Emissions related stuff the ECU has to complete the emissions cycle first.

 

5 miles after installing the sensor the CEL went off on its own. Then about 5 miles later it came back on.
It’s been a few hundred miles since I changed it. City and highway.
I disconnected the negative terminal 15 mins ago.
CEL off for now. Will update tomorrow after my drive back from Chicago to Michigan. Hopefully with good news.

 

Fingers crossed, although I suspect there's still an issue then if the code went away on it's own and then came back. If it comes back again you'll know for sure, in which case I would redo the O2 sensor install for the peace of mind knowing there wasn't an issue there. If that doesn't work then I would try to return that sensor for another one.

 

At this age of vehicle it would also be worth checking the wires, who knows what the DPO did to them.

 

According to this, P0136 can only be caused by a failing sensor, failed wiring to the sensor, or a leak in the exhaust before the sensor

https://www.yourmechanic.com/articl...it-malfunction-bank-1-sensor-2-by-jay-safford

 

Drove about 200 miles, and went through a tank of gas today. About 2 hours of sitting in Chicago traffic, then 2 hours of highway driving home. No CEL.

 

I feel like this is a stupid question but I have the p0446 code as well, would a hole in my exhaust cause that?

 

That one usually points towards a loose or bad gas cap, or an aftermarket gas cap (should only use OEM ones).

A leak in your exhaust would trip a p0420 code, or a bad o2 sensor code like p0136