All four oxygen sensors have codes at the same time, PO135, PO141, PO155 and PO161

Tiny
MATTHARSHMAN
  • MEMBER
  • 2007 FORD EXPLORER
  • 4.6L
  • V8
  • 4WD
  • AUTOMATIC
  • 220,000 MILES
All 4 oxygen sensors throwing a code at the same time

All Heater circuit what could cause this I don't believe all can fail simultaneously like this.

Po135
Po141
po155
Po161
Thursday, July 7th, 2022 AT 6:25 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

I totally agree. These wouldn't all be set at once for no reason. By chance, did it happen after getting fuel? Also, is there any coolant or engine oil being consumed? Is the engine oil clean and uncontaminated? Does it have a fuel smell, or does it appear like coolant could be entering it? Let me know if either oil or coolant is low.

For all of these to be set, there must be some type of contamination in the fuel system. Let me know if you have a live data scan tool. If you do, I need you to watch the voltages of each oxygen sensor. They should change between.1v and.9v. See if they are in that range and moving. Also, check the short-term fuel trims and let me know what they are at operating temperature.

Let me know.

Joe
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Thursday, July 7th, 2022 AT 8:37 PM
Tiny
MATTHARSHMAN
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I changed the oil myself no signs of coolant no consumption of oil or coolant I did find a bad negative battery terminal that I just finished replacing loose enough to possibly connect and disconnect during travel I'm not sure If this would cause the Issue or not either if bank 1 sensor 1 and 2 loose ground.
And same for bank 2 if it would trigger. I don't have a live scan tool. Oddly enough this has happened post fuel pump and fuel filter change and now I also have an EVAP code that I questioned in another thread I'm not sure if all this is related but prior to fuel pump no codes.

Thanks for your help.
Matt
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Thursday, July 7th, 2022 AT 8:43 PM
Tiny
MATTHARSHMAN
  • MEMBER
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Also, I have cleared the codes several times and after a short operation the light and the codes all reappeared.
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Thursday, July 7th, 2022 AT 8:46 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Did they reappear after you repaired the battery terminal? Also, have you checked to make sure there are no engine vacuum leaks? If it is running lean enough, that could put the sensors all out of range.

Matt, let me know if you can get your hands on a scanner that provides live data. I have a feeling something has come disconnected when the work was being done.

Also, check to make sure there are no leaks. Here is a link that explains how to check:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know.

Joe
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Thursday, July 7th, 2022 AT 9:26 PM

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