I Had an On-Board Diag done on my 96 Explorer (4.0L V6 2WD).
PO135 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
PO141 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
PO155 - O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

I replaced all 3 sensors about 3 days ago and had codes Cleard.(No Universals Used)

Now I am getting a PO135

I had replaced Bank 1 Sensor 1 & Sensor 2 about 45 days ago.(Assuming that the two forward sensors are Bank 1)

Questions:
Which forward sensor is Bank 1 Sensor 1?

Could something else be causing the code?

Could something be damaging the O2 Sensors?

More info:
Non-Stock gas cap does not fit like the original.
Can sometimes smell raw fuel with engine running.(Window down)
Oil Pressure is Low.


Thank you.

 

>I Had an On-Board Diag done on my 96 Explorer (4.0L V6 2WD).
>PO135 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor
>1)
>PO141 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor
>2)
>PO155 - O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor
>1)
>
>I replaced all 3 sensors about 3 days ago and had codes
>Cleard.(No Universals Used)
>
>Now I am getting a PO135
>
>I had replaced Bank 1 Sensor 1 & Sensor 2 about 45 days
>ago.(Assuming that the two forward sensors are Bank 1)
>
>Questions:
> Which forward sensor is Bank 1 Sensor 1?
>
> Could something else be causing the code?
>
> Could something be damaging the O2 Sensors?
>
>More info:
> Non-Stock gas cap does not fit like the original.
> Can sometimes smell raw fuel with engine running.(Window
>down)
> Oil Pressure is Low.
>
>
>Thank you.

Bank one is the side of the engine with cylinder #1. On your 4.0L it is the passenger side. Sensor 1 is the sensor before the catalytic converter. Bank 2 is the exhaust side on the driver's side. Sensor 2 is after the catalytic converter. So, bank 1, sensor 1 is your O2 sensor before the cat, on the driver's side exhaust manaifold (or between it and the cat). A bad cat can take out the sensors but 45 days seems a little too soon (not sure though). I also don't think a bad cat can cause a heater failure on your sensors. Usually a heater failure is the result of a bad sensor or wiring issue (bad connector or wiring). When your cat fails you will usually get a low efficiency error (can't remember the code # off the top of my head). A bad fitting gas cap will cause a P0455 error (Gross fuel leak detected), not an O2 error. Smelling raw fuel can either be a leak in the emissions system (fuel lines, gas cap, charcoal canister or canister check valve). I you have a leak in these you will get an appropriate code. If the only code you are getting is related to your O2 sensors, then what you are probably smelling is an overly rich running engine due to a bad sensor. I have seen several people report getting a bad O2 sensor from the parts shop. Maybe you got a bad sensor, or replaced the wrong one since bank 1 is not the front two as you originally thought.

 

[updated:LAST EDITED ON 10-Dec-02 AT 04:46 PM (EST)]
OK, Im sorry but you lost me

Front Drivers Side Sensor________________?

Front Passenger side Sensor______________?

Sensor after CAT._____________?







If I installed a Bank 2 Sensor on a Bank 1 position, Would that possibly cause the PO135

Thanks a bunch

 

No, installing a bank 2 sensor on a bank 1 side will not cause a heater failure. The only difference between them would be the length of the wire. On mine bank 1 & 2 fronts are the same part number, the two rears are also the same part number.

You have an exhaust manifold coming out of each side of your engine. One is on the driver's side (the side with the steering wheel). The other side is the passenger side. Hopefully I don't loose you here, but that is typically the side where the front seat passenger would sit since you could have a rear seat passenger on the driver's side). From each exhaust manifold, you have a pipe that connects to another pipe that is shaped like a 'Y'. The outlet of the 'Y' goes into your catalytic converters. After your catalytic converter is another pipe that goes into your muffler.

You have three O2 sensors. One is mounted either on the passenger side (bank 1) exhaust manifold or the pipe from that manifold to the 'Y' pipe. One is mounted either on the driver's side (bank 2) exhaust manifold or the pipe from that manifold to the 'Y' pipe. These two O2 sensors are called the pre-cat sensors (front). One is on bank 1 and one is on bank 2. Your third O2 sensor is on the pipe between your last catalytic converter and your muffler. For simplicity sake Ford states that it is on bank 1. This is your post-cat sensor (rear). On '96 Explorers and newer they are all electronically the same. The only difference between them is the length of the wire.

On the SOHC and V8 there are 4 O2 sensors since the two exhaust manifolds go into their own catalytic converter(s) which then each individually go into a 2-inlet muffler. They have two upstream sensors (1 on each bank) between the exhaust manifold and the catalytic converter. Then there are 2 more O2 sensors between the catalytic converter (1 on each bank) and the muffler.

 

Also to maybe more clearly answer your question:

>Front Drivers Side Sensor=__bank 2, pre-cat (upstream)__?
>
>Front Passenger side Sensor=__bank 1, pre-cat (upstream)__?
>
>Sensor after CAT.=__bank 1, post-cat(downstream)____?

 

OK, Now all 3 codes have came back again.
After replacing ALL 3 O2 Sensors.
PO155, PO135, and PO141.

What is the deal here?

 

I will buy your old ones

 

possible fp regulator,or injector leaking.causing excessive gas,and thinning oil,change oil see if oil pressure comes back.then fix injector or regulator thats causing excessive fuel flow.ps note colors on o2 sensors don't mix up and down stream.let us know how you make out.

 

Color of 02 Sensors?
Please explain.....

Thanks

 

upstream should have green plugs,downstream blue

 

When changing oil in the past it only just brought the oil press. out of the red(Minimal increase).
The wiring harness side is green b4 cat.x2 and blue or black after the cat. All Sensors are white connections.

Is there a backyard way to check regulator pressure and Injector pressure?


Also, I had disconnected the power from AC Compressor to keep it from coming on when running heat. (Is that Normal?)
I thought maybe it may be linked and hooked it back it, and now I am getting 4 codes.
Old PO135,PO141 & PO155
New PO136 (O2 Sensor Heater Circuit Malfunction) dont rem. bank#.)

one opinion is the MAP or MAS. Seems life I have heard it called both.
Mass Airflow something....

 

sounds like wrong hegos.i guess they are not ford replacements.the sensor plugs must match motor harness colors.ford hegos should be used.

 

map on eccv = bap on ecc iv measures atmospheric pressure.

mass or maf same as mass air flow.you are not getting these codes so don't worry.

get the correct hegos for your truck from ford.

a fuel pressure gauge will tell you your fp.leaky injectors are harder to diag just replace if over 100k.but since all codes lead to hego system repair that first.

good luck

 

ac will come on and cycle in every selector position except vent only and off