Oxygen sensor

[crazy cajun]

Does any one no how to test O2 sensors so that all 4 does not have to be replaced only the bad one??

[hundahunta]

any codes. what lead you to thinking a 02 sensor was bad??

[crazy cajun]

Came up in my inspection report O2 sensor was not reading was told maybe only 1 was bad but would have to replace all 4 so that the right one was replaced kind a expensive thou

[praisethelowered]

You can check the resistance of each sensor individually and see if they are within spec (although I don't know what those specs are). Some advanced scan tools can do this with the sensors installed and the vehicle running.

[BleedDodge]

That's what they want, they want you to pay them to replace all of the sensors so they can make money off you. If they know a sensor is not taking a reading, then they will be able to narrow it down and tell you which one it is.

The sensors on the engine side of the catalytic converter take oxygen readings for the engine to run from, and the sensors on the exhaust side of the catalytic converter take oxygen readings to be able to tell the computer whether or not the cat is doing its job. If they can't get a reading from one of these sensors, they can certainly tell you which one has malfunctioned.

[crazy cajun]

bleeddodge
thats a good looking truck look just like mine even the same color only i have the round chrome tubes for steps and a cheaker plate tool box on it

[BleedDodge]

Cool.

Your truck will only have 2 oxygen sensors, a pre-cat and a post-cat. The pre-cat sensor, on the engine side, is the one you should try and replace first. If that sensor isn't working properly you'll probably be getting bad gas mileage, and your check engine light is probably on.

I'd replace that first sensor and see what that does. A sensor is probably around 50 bucks American, but I don't know how much an inspection costs. You don't want to go back and spend money on an inspection again and fail it...

[crazy cajun]

[If that sensor isn't working properly you'll probably be getting bad gas mileage, and your check engine light is probably on.]

That is true but mine does have 4there are 2 in front of the cat. Converter and to in the back I have dual exhaust with flow masters

[BleedDodge]

Ohhhhhhh. Okay. Change the 2 in front then. Try that before anything else.

[JoeThe Mech]

If it has a an O2 not reading you should have a check engine light on or at will at least have a code stored. The code will be specific as to which O2 it is. Only the bad O2 should be replaced, it is not necessary to replace O2 sensors the are working good. You will need to find someone who can retrieve codes to get this information.

[crazy cajun]

joe
i have checked for the code using a chilton book and turning the switch on and off 3 time fast then turn on and count the numbers for codes and it is reading bad o2 sensor the check engine light comes on for a couple of days then it goes back off it doent stay on all the time gas millage is real bad when the light is on but once it goes off it gets better.

[BleedDodge]

Yeah one or both of the oxygen sensors are probably working correctly until they reach a high temperature or something. Whatever the case, change 'em both.

[hundahunta]

if you have a check engine light on, there is no possible way that they could not tell which sensor it is...your vehicle has 4 sensors, the 2 front are the main sensors.

[BleedDodge]

Sure you can tell. We already know one of the sensors is buggered because his inspection report said so, so you can find out just by what codes you get.

What if you get a code that tells you that the cat is inefficient or inoperative, like a code 64? Your rear sensors would be messed up then. We know this statement is true since the inspection found nothing wrong with the cat, but with a sensor.

What if you got like a code 51 or 52? These would mean the sensors were stuck at lean and rich, respectively. You would then know that one of the oxygen sensors in front, the pre-cat sensors, are messed up.

[crazy cajun]

bleedDodge

That is correct the code i get is 52 O2 sensor but even tho the test showed the sensors were not working after taking the test (reading) it past but was told it needs to be repaired by the next test.