Air/Fuel Sensor Help Needed

Ive searched and read just about every post about this topic but it seems like every thread is just left hanging. I just forked over $200 for a new sensor put it in, drove to advance to have the code removed. I drove about 10 miles and guess whos ugly face reared its head? You guessed it the same damn cel. I spoke to one of the mechanics at my local dealership and he told me it could be anything from a loose gas cap to the ecm going bad. Real specific huh? What Im looking for is actual help. What have yall done to get that damn light to stay off? Any help is greatly appreciated!!!!!!!!

 

Well when I did mine, my CEL came back too, and It so happened to be rear censor went bad too.
When replacing o2 sensors you should always replace both because the new and old will read differently. But not only this, but you could also have a exhaust leak or a bad cat.
I would first check for leaks, and then make sure that your cats are indeed good, then after that, You should most def. change the rear sensor! RockAuto.com has great prices on censors.

 

how do i check for leaks on the cats? Please over look me not very mechanically inclined

 

^^^ Yeah, that too!
Im assuming its the P0420, bc of the sensor change though... my bad!

 

going to have the codes pulled today will post later

 

Ok just got back from Advance and guess what code popped out. Thats right 135 but it brought a buddy with him P1133, The guy at Advance told me that the sensor was bad and got a chuckle when i told him i just put it in Friday. Any ideas what to do to get rid of that light short of ripping it out?

 

Did you switch it out with the same OEM Denso sensor?
My next geuss would have to be either faulty sensor and or bad connection. I would still recommend changing both at the same time though, but thats just me....Sorry Bud!

 

ok after pouring over the service manual I think i may have my culprit. I believe it is the EFI Main Relay. I swapped relays with the pwr outlet relay and unhooked the battery. Im gonna let it sit for a while and see what happens. Im gonna figure this damn thing out if it kills me

 

Well the EFI Sensor was a no go too. Still working on it though will keep yall posted on my progress or lack there of. Going to pull the glove compartment out tomorrow and check the ECM

 

Think I may have it figured it out but not sure for real. I took out the glove compartment and checked the connector to them ecm making sure all the wires were well seated in the connector. I crawled under the truck and unhooked the afr sensor cleaned the ends with electronics cleaner reconnected the plugs making sure the wires were seated well in the plugs. I got the OBD 2 out cleared codes, started the truck and let it run for about half an hour and no codes (yet). It got late on me so I havent had a chance to get it out on the road and check things out then. Will try to do that tomorrow after work and post any results.

 

Wrong again. This really is gonna be the death of me. Last night while I was installing my Billys 5100, my Taco fell off the jack stands. Luckily noone was hurt. But when it hit the ground it cracked my exhaust pipe right at the flange before the cat. When I started the truck the check engine light went out. Think the cat is bad or something before the cat? This one has really got my confused.

 

Dude, if your truck is driving fine, dont sweat that frigg'n checklight. 9 times outta ten its one of the o2's. Buy yourself a reader, I can reccomend the actron Pocketscan cp9125, $60 in Sears, it'll affirm the codes for you, then reset them, bye bye light.
Fell off the jacsktands?? Now Hey, Let's be careful out there....
[Lt Ousterhuse, Hill St Blues]

 

Problem is its not really driving fine. She drinks gas like an drunk at an open bar. I know its not the sensor. I bought a universal one to start off with hooked it up reset the computer started the truck and the cel came on immediately. I had read that universals were hit and miss so I figured I missed with this one. So I bit the bullet and went to the dealership for an oem sensor installed it had the computer reset and got about 10 miles down the road before the light came on again. Its the same code that Ive been getting since I bought the truck 2 yrs ago P1135 Air/Fuel Ratio Sensor Heater Circuit Malfunction. I have been told that if I dont get this fixed it could potentially damage other parts including to MAF sensor and let me tell you they dont give those things away.

 

Check out www.enginelighthelp.com , punch in the code, and see what other suggestions ...

 

I actually think I have figured it out now. Pretty much had to pull my whole dash out but on one of the connectors going to the ecm one of the wires going to sensor isnt getting any juice like it should its also real loose inside the connector. Now just trying to figure out how to fix this.

 

Fingers crossed for you man...

 

Well after everything was said and done, the problem was (DRUM ROLL PLEASE)............Bad ECM Doh! Got tired of messing with it so when my appointment came up for the recall I begrudingly paid to have the stealership hook up to it to see what the problem was. After about a min and $90, the mechanic informed me that it was the ecm. I hope you are sitting down cause when I asked how much for a new one, he kinda chuckled and said, " Oh about $1000." I thought they were gonna have to help me up off the floor. Luckily, I found a used one on Ebay. When it comes in, Ill let yall know how well it works.

 

How much was the eBay ECU? My CEL came on w/ a P1135 code. A day later, the light went off (right after I ordered A/F and O2 sensor!) I am getting ready to hit 125k miles so it is probably a good idea to change them anyway. My 2000 Tacoma, same specs (fewer miles) used to get 19-20 MPGs after I changed sensors, this truck has NEVER seen 20 MPG...I don't even think 19.5.

Glad to hear you got it figured out though! What else can you recall about what you found in the dash (loose wires?)

 

I got it for $115 should be here Tuesday. As soon as I get it installed and run it for a little while Ill let ya know if that really fixed the problem.