I have a 1997 F150 4.6 V8 and i have recently gotten a check engine light and the codes are for the rear oxygen sensor on both sides. I checked a few wire diagrams and it showed that there is 4 wires going the oxygen sensor: 1 gray, 1 black, and 2 whites.
Now the whites are for the heater part, and 1 white should be a 12volt wire and the other white should be the heater ground. Heres the problem, both of my white wires have 12volts going to them. Is it possible there is a short or what. I am really confused! All help would be great thanks.

 

if your 02 were that messed up the truck would even run right??everything has to be grounded somewhere. try the guys in the electrical section , sure you will get more info..

 

Like the other poster said, post this in the electrical section. There's some guys here that REALLY know their stuff. In the meantime, the malfunctioning rear O2 sensors don't directly affect any engine related calculations. But if you have an unusual electrical problem, it in itself might be a problem.

 

These threads should be consolidated.

https://www.f150online.com/forums/sh...d.php?t=270894

 

Ifgnore the previous responses from individuals who are not versed in electronics.

It is completely normal for both heater wires to show battery voltage most of the time. The only time the heaters are energized is during cold engine startup to assist the sensor element if getting up to operating temp. Once that point has been reached, the heaters are then turned off and left off until needed for the next cold startup.

The one side of the heater element is always hot while in RUN. The heater is turned on by the PCM by grounding the "low" side of the heater, thereby allowing current to flow. When the heater has finished its job, the PCM removes the ground and the current stops flowing. With no current flow in the circuit, all points in the cicuit will then show supply voltage.

If you don't understand this, don't feel bad. It is an electronics concept that can be difficult to grasp by someone without the proper basic electronics and electrical training.

Steve

 

I understand that but how can I get my error codes to shut off. I posted in my other post but they are P0141 and P0161 which are heater malfunctions
I know my o2 sensor heaters are bad and I got them resistors from a store (I know i am cheap) to hook up, but the company said there should be a heater ground so they can work properly. This is why I need that ground to turn the check engine light off.

 

Your heaters aren't bad if you get 12 volts on both sides. That shows they are continuous (good) but turned off or disconnected on the control side. The heaters are grounded by the PCM. Looks like you have a bad ground or wire somewhere.

 

ok heres my question now, what do I do.. I have them resistors that claim to work, heres the site http://mysite.verizon.net/vze7erz1/s...les/dualo2.pdf

on page 3 theres the NON GM type dual exhaust set-up wchich uses the resistors and dualo2sim. now tell me what you think. It shows to use the heater wires to hook to the resistor.

 

Are you installing the resistors and the Sims? The resistors replace the heaters. They are connected to the same wires the heaters are connected to INSTEAD of the heaters.
This alone will not fix your problem.

 

they are in place of the heaters. originaly i hooked up the simulator and i had 1 error code saying one of my rear o2 sensors were bad. then i disconnected both and hooked the resistors up right and now is reading both sensors are bad. Which would mean the resistors are doing jack shi*
There has to be a way to fix it.

 

Do you also have the sims in place?

 

yes it is one simulator but has wires to simulate both rear o2 signal wires.

 

Figure 4 in the instructions is how you should have everything wired. Remember you should only use the resistors or the heaters but not both.
Why are you installing this stuff? Your heaters are good according to your measurements. Your problem lies elsewhere.
The heaters are only used on cold start up. After that it doesn't matter.

 

I starting installing this stuff because I had error codes. So I know i need the simulator because my cats are bad. like I said when I first put the simulator on, only one error code was reading which was the P0161. So if i reconnect that o2 heater, i will still need to fix the other o2 heater.
How does one side work and the other doesn't with the stock o2 sensor heaters? I feel some meter testing coming on tomorrow