for the past week i have been getting the check engine light coming on in my 2000 5.4. i have the edge evo so i can look at them and clear them, i clear them but it comes back with in time...i keep getting the P0136 code for circuit malfunction and the heater circuit malfunction....i looked up the code and it says the rear O2 sensor is bad or something....that makes no sense to me ,because i have OBX long tube headers, and on the rear O2 sensors i have the eliminator kit on both back ones....why would it be setting off the code for the rear if they are eliminated?????


any help please!!!

 

P0136 Heated O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)

I would think that something is wrong with the eliminator itself. Could be the wires or the harness going to.

You could try swapping eliminators to see if the fault returns on B2S2 to test.

I just searched it - there really isn't all that much info about it pointing to a common problem. How long has this been installed before you had the fault?

 

well i installed the headers and all my exhaust in about October of 07...i then just ran the truck for a long time with the O2 sensors unplugged because i didn't know what to get to make them work with the headers...then about a good month ago i got the O2 sensor extensions for the front ones and the eliminators for the back ones...everything worked great until about 4 days ago. the eliminators are not that old.

 

The rears just check your CAT efficiency and with regular O2's back there you would be getting a PO420 and PO430 without cats. I have LT's on my 5.4L as well - but I'm running High Flows (cats) behind the Y and all 4 O2's.

Your code doesn't cause a drivability concern, the rears reading don't in any way adjust ratios - Their just CAT checkers. Your front O2's are the important ones and you don't have a problem there.

You have two eliminators right? I would swap them and check the wires real good when doing so. Swap them to determine a hardware problem. If you get the same code on Bank 2 after swapping, then you have a bad product.

Make sure you reboot the comp. In fact , I may try that first before going thru the trouble of swapping them. I wouldn't rely on the tuner to erase the code , I would pull both pos and neg terminals for at least 20 minutes for a full reboot.

That reminds of a problem I had with the rears once though. When my EGR pipe was leaking @ the header , I had a Bank one rear O2 code as well. I thought that was strange. After I installed a new EGR pipe that didn't leak , the code never reappeared..? Oh well, stranger things have happened

 

what are the eliminators? cause im getting code po430 , changed both O2 sensors on passanger side and still getting the code . i just purshased the truck its a 2006 f150 5.4 with 72000 kms on it . what do i start checking now ?