Contour Enthusiasts Group Archives Forums General Troubleshooting CEL CODE PO136

Ok my wife hit a coyote in her 99 tour and I had to replace the Radiator and A/C Condensor. I got them rreplaced and then the CEL came on took it to Autozone and it reads P0136
They said it was a bad O2 sensor and it was the one at the front of the engine. I replace it and had the code erased then the next day it came on again same code. So I did some reseach and I found out that the code I think reads this (P0136 HO2S Circuit Malfunction Bank 1 Sensor 2) Can Some one help out we are leaving town this Friday and we need to take the car and the drive is 4 plus hours so I really need the problem fixed, can some one please help me.

Bank 2 is downstream, so if you replaced the one on the front of the engine, you replaced an upstream sensor.


Ray

Ok I talked to the local Ford dealer and a person there said that the on that I need to look at is the on right under the engine they said it would be really close to that radiator and it would be next to the front cross memeber of the car. He said it is easy to see it is kinda at the bottom of the Header. Does that sound right for the code P0136. Thanks for the infor on the Banks. . . I hope I can get it running right tonight...

That sounds like the right location which interestingly sounds to be near where your work was performed, so perhaps its wiring.

I've recently been getting this code even though I have new sensors. It may not be the sensor but just faulty wiring.
My Check Engine Light just went off on its own, after it had appeared and I had cleared it. The two times it went on it was raining, so perhaps I'm getting moisture on the wiring.

I guess if the sensor has 70,000 plus miles on it, it can't hurt to replace it. Lots of posts about replacing them,its easy except for another one of the sensors which is the upstream on the firewall side of the engine that can be tougher to reach.

But it seems to me that this sensor going off, since its downstream, is not something that will hurt things if you ride on it. Is the car running fine other than the CEL?

P0136 is suppose to be the O2 on the Firewall side. I just replaced it and now have all 3 O2s replaced since the 1st of the year. I drove the car almost all day and it was fine, until it got dark outside and then the CEL came back. Same code. I'm still under warrenty, so it's going in on Thurday. I'll let you know. But I have been driveing on the code for 2 or 3 monthes with the code.

All three? there are four O2 sensors... bank 1 and Bank 2, each with two sensors..



Ray

Ok here is the deal I have now replace the one at the front of the engine and now also the one right under the raditator on the pass. side of the car. Drove it for 60 miles and no light, got up to go on the trip and drove 3 miles and it came on. From reading the post so far it was raining out that day and the night that we test drove it it was nice out. The car seems to be driving ok. So this morning I had her drive the car to work to see how it drives. I think that I might just give up on the car and let it stay on. We were planing on trading it in in Dec. but I think I might push for it to be sooner. I talked to several people this weekend and they said that the code was for Bank one sensor 2. I had it scanned at Autozone and that is the what the code said. P0136 Bank1 sensor 2. Can anyone shed some light on this thing. PLEASE. . . . .

Bank 1 Sensor Two Is The Downstream Right In Front Of The Main Catalytic Converter IIRC. Bank One Sensor One Is The Hard One...Its On The Header Closest To The Firewall.
Bank Two Sensor One Is On The Header Closest To The Radiator, And Bank Two Sensor Two Is The One Lower To The Radiator...Someone Correct Me If Im Wrong...

If You Do A Little More Research Youll Find That There Are Several Things That Can Trip An o2 Sensor Related CEL. IIRC The PO136 Is For A Heater Circuit Malfunction On The O2. You May Be On The Right Track Thinking About The Wiring. The Code Is Basically Telling You That The Catalysts Are Not Lighting Off At The Correct Or Optimum Temp. Somebody Yell If Im Incorrect!!! It Could Be Anything From The Wiring Having Moisture Built Up, To The Cat. Going Bad.
The Reason The CEL Came Back On Is That The Computer Will Try To Diagnose And Compensate For The Problem For Three Key Cycles. If The Problem Persists, Then The CEL Will Come Back On....So, Basically You Didnt Fix The Problem.