Electrical Question:All Four O2 Sensors Fail at Same Time???

[Rottwheeler]

So the check engine light is on in my LJ. I purchased a Bluetooth OBDII adapter and downloaded an OBDII Scanner App (Torque) to my Android phone and find that the error codes indicate all four O2 sensors have failed. Is it typical to lose all four at the same time?

These failures occurred on the heals of me attempting to install a hard top wiring kit to supply power to the rear window defroster and wiper. I say attempting because the install isn't finished... as the installation instructions I received do not match the instrument cluster and body connectors installed on my vehicle. So... I've obtain additional circuit diagrams from the dealer to try to identify the proper pin locations in the connectors that are on my vehicle. Fun...

Anyway, while it seems unlikely to me that the unfinished hard top wiring kit could have caused the O2 sensor failures... the timing of the events leads me to think there is some connection (no pun intended).

Thoughts / experiences???

[Wrench]

Possible, though I really have no knowledge of the electrical system to know. 9 times out of 10, I see electrical issues caused by someone tapping into the factory systems.

I DO know that silicone can ruin O2 sensors. If you used silicone as a sealant for something on the engine, or ran something silicone-based through the engine, like a lube or something.

[Lurch]

Do you have a code description(lean, heater circuit failure, rich, ect)? I would be tempted to think you may have messed with the wrong wire or blew a fuse that goes to the o2 sensors and possibly powers something else that you may have accidentally tapped into.

[Rottwheeler]

Do you have a code description(lean, heater circuit failure, rich, ect)? I would be tempted to think you may have messed with the wrong wire or blew a fuse that goes to the o2 sensors and possibly powers something else that you may have accidentally tapped into.

"Powertrain HO2S Heater Control Circuit Low" is the message on all four faults with P0031 = Bank 1 Sensor 1, P0037 = Bank 1 Sensor 2, P0051 = Bank 2 Sensor 1 and P0057 = Bank 2 Sensor 2.

[Lurch]

You def did something. Check your fuses first. Then check your grounds for the o2 sensors. Double check any wires you messed with.

[TJDave]

My friend Gerald is dealing with this right now on their 05 X. Same codes, running a little rough. He replaced all 4 O2 sensors with no luck. I did a little reading and found some interesting things.
A clogged cat will cause similar symptoms and codes.
Check for blown fuse under the hood.
If a sensor wire has rubbed anything on its trip up to the engine compartment, it could also throw the codes.
I also read that TJs are a little picky on which brand sensors you buy, but I forgot which brands are the sucky ones.

[mattawajeep]

I'm with lurch on this one. Sounds like you've messed up either a fuse, power wire, or ground wire the 02 sensors.

The O2 sensors on your LJ have a built in heater and I'm betting they're not getting power. Take a voltmetet and check for power at a sensor, and continuity on the ground.