Code for all 4 O2 sensors popping up

[OR VietVet]

Cats can get clogged and that may only show at certain times depending on the damage inside. A back pressure test is a good way or temp measurement from front to back after hot and temp difference side to side. Clogged exhaust can also give you a loss of power and bad vacuum readings.

This says it better than I can explain:

After the vacuum gauge is connected to a vacuum source, readings are noted at idle and then again at 2,500RPM. As engine speeds vary, readings should initially drop slightly, then rise to within 2-3" of the vacuum level established at idle. A large drop of 8-10" of vacuum typically indicates an exhaust restriction.

 

[afpj]

Did you check fuses? I think with my 2002, there's a specific fuse for the heater circuit for the O2 sensor

 

[swathdiver]

Wow I wasn't expecting all the quick responses! thanks everyone for trying to help out so far. i currently have 5 codes, i figured the last code (P0410) was worth asking in this thread as well. I'm still learning how to use this forum so i apologize if a lot of information is missing. If i need to give any more information, do let me know. As for getting numbers while idling and etc that Fless has asked for, i will try and get them tomorrow as early as possible

As for the O2 sensor codes:
P0135
P0141
P0155
P0161

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That's what I thought, you might have a wiring problem. A critter may have chewed through some wires further up along the wiring harness. If all that looks good, it's time for a new engine computer. If you wiggle the wiring and the values change, then it's wiring. If not, computer time.

 

[Danie Lizarraga]

Thank you everyone for the advice i will check on all these things after the rain is gone

 

[OR VietVet]

 

[JEFFC]

The o2 codes that you have are all for the heater circuit, not the actual sensor circuit (that would be different codes). A bad o2 heater can cause the codes that you have but the chances of all 4 going bad at once is nearly impossible. Do not replace anything until you verify that the heater circuit is good, Start with the fuse. All that the o2 heater does is allow the o2 sensor to warm up faster, giving the computer a more accurate reading during the first few minutes of operation. The heat of the exhaust keeps the sensors hot within a few minutes of starting and the heater is no longer needed. The other code that you have has to do with the air injection system which also only runs during a cold start and is monitored by the o2 sensors. Disregard the air injection code until the o2 problem is solved. Since you have the 5.7L engine in a 2000, that would indicate that you have an old body style Tahoe. There was a mid year change in 2000 to the new body and 5.3 engine. To avoid confusion when doing an internet search, plug in 1999 Tahoe instead of 2000.

 

[Danie Lizarraga]

The o2 codes that you have are all for the heater circuit, not the actual sensor circuit (that would be different codes). A bad o2 heater can cause the codes that you have but the chances of all 4 going bad at once is nearly impossible. Do not replace anything until you verify that the heater circuit is good, Start with the fuse. All that the o2 heater does is allow the o2 sensor to warm up faster, giving the computer a more accurate reading during the first few minutes of operation. The heat of the exhaust keeps the sensors hot within a few minutes of starting and the heater is no longer needed. The other code that you have has to do with the air injection system which also only runs during a cold start and is monitored by the o2 sensors. Disregard the air injection code until the o2 problem is solved. Since you have the 5.7L engine in a 2000, that would indicate that you have an old body style Tahoe. There was a mid year change in 2000 to the new body and 5.3 engine. To avoid confusion when doing an internet search, plug in 1999 Tahoe instead of 2000.

I just checked the fuses with a volt meter and they are good, it has a 30 amp fuse instead of a 20. I don't think it would make that big of a deal would it?

and yes i do have the old body style tahoe

 

[JEFFC]

Sorry for the delay, kind of crazy around here with all of the fires. The 30 amp fuse will not stop the circuit from working. The higher than rated fuse could indicate that the previous owner was having a problem with the circuit blowing fuses and tried a larger fuse. The larger fuse could have caused the previous short to fry and is now an open circuit. You need to find a mechanic that is good with electrical and trace the system.

 

[Doubeleive]

I would check that 02 heater circuit with a meter, @swathdiver do you have the info for the 02 heater circuit on a obs? ohm's check?

 

[swathdiver]

I would check that 02 heater circuit with a meter, @swathdiver do you have the info for the 02 heater circuit on a obs? ohm's check?

Don't think so, will check after work. If all the wiring checks out it's probably the ECM.