O2 sensors
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From: SaN AnGeLo
O2 sensors
I purchased a new magnaflow exhast system with dual mufflers, x-pipe, and 2 high flow cats. It was recommended to change out the o2 sensors because it was a good maintainance thing too do especially with over 150,000 miles. I changed the sensors out 3 months ago and and now receiving the bothersome check engine light. I went to autozone to get a diag, and was told that its the 02 sensors. Does anyone know what could have caused this? Does boush make crappy sensors? Is there something i should check before i change the sensors again? To top it off the part store where i bought it says they dont have a record of me purchasing the sensors from them and will not warranty them. Any help would be appreciated.
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From: Mpls, MN
Do you have have the code??? Having the actual code would be very useful.
I'll bet it was just a code that said "lean bank 1 and 2." Because they don't really diagnose, they just guessed it must be the O2 sensors.
If the O2 sensors were replaced a few months ago, I'm sure they're fine. I also threw a lean code after having a dual exhaust installed. It was because the MAF was dirty and not measuring all of the incoming air. The next sensor to measure air, after the MAF, is the O2 sensor.
Try cleanning the MAF and see if the code goes away.
I'll bet it was just a code that said "lean bank 1 and 2." Because they don't really diagnose, they just guessed it must be the O2 sensors.
If the O2 sensors were replaced a few months ago, I'm sure they're fine. I also threw a lean code after having a dual exhaust installed. It was because the MAF was dirty and not measuring all of the incoming air. The next sensor to measure air, after the MAF, is the O2 sensor.
Try cleanning the MAF and see if the code goes away.
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Joined: Jun 2002
Posts: 10,511
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From: Under the flightpath of old ORD 22R
Lean codes can also be caused by exhaust leaks before or near the O2S sensors.
If you are getting a P017x code, this is one of the things to look at, maybe.
Here is the thread where another had P017x code, and the list from the Ford Manual on what to check, if that is the code you get.
https://www.f150online.com/forums/sh...hreadid=101648
Else post the code number, and myself or another will look it up for you.
Neal the HP freak siad that the Ford O2 sensors are made by Bosch, and Bosch is usualy the brand of wideband O2 sensor that wideband A/F ratio gauges use.
or maybe you got a faulty O2 sensor, but you should get a differnet code then a P017x if it i a faulty O2 sensor
If you are getting a P017x code, this is one of the things to look at, maybe.
Here is the thread where another had P017x code, and the list from the Ford Manual on what to check, if that is the code you get.
https://www.f150online.com/forums/sh...hreadid=101648
Else post the code number, and myself or another will look it up for you.
Neal the HP freak siad that the Ford O2 sensors are made by Bosch, and Bosch is usualy the brand of wideband O2 sensor that wideband A/F ratio gauges use.
or maybe you got a faulty O2 sensor, but you should get a differnet code then a P017x if it i a faulty O2 sensor
Technical Article Contributor
Joined: Jun 2002
Posts: 10,511
Likes: 10
From: Under the flightpath of old ORD 22R
DTC
P0141 - HO2S Sensor Circuit Malfunction (HO2S-125)
Description
See DTC P0135
Possible Causes
Diagnostic Aides
DTC
P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
Description
During testing the HO2S Heaters are checked for opens /shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and /or an open or short is detected.
Possible Causes
-Short to VPWR in harness or HO2S.
-Water in harness connector.
-Open VPWR circuit
-Open GND circuit.
-Low battery voltage.
-Corrosion or poor mating terminals and wiring
-Damaged HO2S heater.
-Damaged PCM.
Diagnostic Aides
-wiring.
-Damaged HO2S heater.
-Damaged PCM.
This is the list from the Blue Oval.
Bewarned of AutZone Techs, they usually read the DTC def, and tell the person to replace that, even though that is technically the reporting device.
Several people have returned O2 sensor that they bought at the suggestion of the AutoZone tech, when all they had was a simple problem like a leaking vac line.
While this may not be the case of yours, you might want to check through the list above, before going through the pain of replacing the O2 sensor ( which you will note is the 2nd from the bottom of the list, not #1 ).
Maybe checking that the O2 sensor wiring harness did nto wind up against the new system, and the wires got burnt through ( just a huge swag ?? ).
Anyway, thought you might find this interesting reading.
Good luck and us know what the outcome is.
P0141 - HO2S Sensor Circuit Malfunction (HO2S-125)
Description
See DTC P0135
Possible Causes
Diagnostic Aides
DTC
P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
Description
During testing the HO2S Heaters are checked for opens /shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and /or an open or short is detected.
Possible Causes
-Short to VPWR in harness or HO2S.
-Water in harness connector.
-Open VPWR circuit
-Open GND circuit.
-Low battery voltage.
-Corrosion or poor mating terminals and wiring
-Damaged HO2S heater.
-Damaged PCM.
Diagnostic Aides
-wiring.
-Damaged HO2S heater.
-Damaged PCM.
This is the list from the Blue Oval.
Bewarned of AutZone Techs, they usually read the DTC def, and tell the person to replace that, even though that is technically the reporting device.
Several people have returned O2 sensor that they bought at the suggestion of the AutoZone tech, when all they had was a simple problem like a leaking vac line.
While this may not be the case of yours, you might want to check through the list above, before going through the pain of replacing the O2 sensor ( which you will note is the 2nd from the bottom of the list, not #1 ).
Maybe checking that the O2 sensor wiring harness did nto wind up against the new system, and the wires got burnt through ( just a huge swag ?? ).
Anyway, thought you might find this interesting reading.
Good luck and us know what the outcome is.
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From: SaN AnGeLo
ok guys i havent been able to give you an update on the code i was receiving because of the tranny prob i ran into. Thank god it was only my torque converter that messed up, and was covered under my tranny warranty. Ive replaced the o2 sensors and checks the wires and everything looked fine to me. i disconnected the battery to get rid of the engine light and the truck was running good for about a day and then the light came back on again. My truck is not running so good anymore. I went to autozone to see if it was the same code, and it was. The guy that worked there said that if i had a receipt for the o2s he would remove the engine code. He says you cannot erase the memory on these trucks. Personally i dont think he was right, because ive been able to fix probs and the code turns off by itself or i can disconnect the battery and it will be fine once connected again. Ive got an opitma yellow top battery and had it checked and it is fine, along with the terminals. I dont see any corossion at all. Whats scaring me now is that the only things left on the list are the vpwr circuit, what exactly is that? open ground circuit, where should i look? and the last that really scares me is the pcm, is that the computer? sorry for not knowing all the places to check but im learning. If you guys know what i should do, please let me know and thanks in advance.
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Technical Article Contributor
Joined: Jun 2002
Posts: 10,511
Likes: 10
From: Under the flightpath of old ORD 22R
Did you try cleanign the MAFS like AjRagno suggested ?
This can also be a problem with the code even though it is not on the list.
The whole thing about the code setting, it the closed loop on emmisions only activates to set a code after driving over 48 mph.
I also think this is one of the codes that is a 2 timer, but I am not 100% sure on that.
JMC also recomended the same fix ( clean MAFS ) last week for lean codes, if I recall the post correctly...?
Try this before you dive in any further, cleaning the MAFS is almost considered routine maint anymore.
Just a thought before you dive in any further with the other things. Just b/c Ford does not list it, doesn't mean it does nto apply when doing mods.
This can also be a problem with the code even though it is not on the list.
The whole thing about the code setting, it the closed loop on emmisions only activates to set a code after driving over 48 mph.
I also think this is one of the codes that is a 2 timer, but I am not 100% sure on that.
JMC also recomended the same fix ( clean MAFS ) last week for lean codes, if I recall the post correctly...?
Try this before you dive in any further, cleaning the MAFS is almost considered routine maint anymore.
Just a thought before you dive in any further with the other things. Just b/c Ford does not list it, doesn't mean it does nto apply when doing mods.
Technical Article Contributor
Joined: Jun 2002
Posts: 10,511
Likes: 10
From: Under the flightpath of old ORD 22R
LoCo F150,
Looks as if you are down to having to check the harness from the HO2S and up the line.
If you replaced the O2 Sensors, and still get this it could be :
1. Damaged harness.
2. a faulty O2 sensor new in the package. You never can tell if this was used by someone else, damaged and they returned it for a credit, and you actually have someone else's O2 sensor from their truck. Unless you are on your second set already, then I woudl home in on the wiring harness & connectors. it is going to be a PITA, but it can be done.
Let us know where you stand.
Steve
Looks as if you are down to having to check the harness from the HO2S and up the line.
If you replaced the O2 Sensors, and still get this it could be :
1. Damaged harness.
2. a faulty O2 sensor new in the package. You never can tell if this was used by someone else, damaged and they returned it for a credit, and you actually have someone else's O2 sensor from their truck. Unless you are on your second set already, then I woudl home in on the wiring harness & connectors. it is going to be a PITA, but it can be done.
Let us know where you stand.
Steve
Member
Joined: Dec 2001
Posts: 15
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From: Texas
Same Code
I have just replaced all 4 sensors on my 1997 F-150,4.2 and keep getting the same code as you. Doesn't really seem to effect the truck unless the A/C is on. Truck has 161,987 miles on it. Please post the solution when you find it , I will do the same if I find it first.