It all began with a check engine light with code PO125 = Coolant Temp Sensor.
I replaced that sensor, cleared the codes a few days later I am now getting codes:
P1133
Air/Fuel Ratio Sensor Circuit Response Malfunction (Bank 1 Sensor 1)
P1135
Air/Fuel Ratio Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
P1153
Air/Fuel Ratio Sensor Circuit Response Malfunction (Bank 2 Sensor 1)
P1155
Air/Fuel Ratio Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)

I do not understand why both O2 sensors would fail at the same time. Is there something else I am missing upstream that is causing the 02 sensors to report malfunctions? I have checked for vacuum leaks, checked coolant level, checked all connections.... Please help!!

 

The most likely cause for all 4 sensors to fail at the same time would be either the A/F fuse, or the A/f relay. Both the relay and fuse are common to all 4 sensors.

 

George,
Thank you for the feedback. I located both the relay and the fuse. The fuse looks good but is there a way to test the relay? Or Would I be better off to just order another in case?
Thanks!

 

You could check to see if the same relay is used for the EFI or ac and swap them. To check for operation, I suggest taking a short section of speaker wire, and stripping back bot ends. Then you could remove the relay, slip the wire into the proper plug, and re-install the relay. These type of electical problems can be caused by several things, it can take a little while to figure out which one is the issue.

 

Did you ever determine what was the fix for this?

 

You realize this thread is over 6 years old and op has posted only two times, both in this thread?

 

If this person is still a member they may have fixed it and forgotten to update. I'm having the same problem and I don't really want to shell out $350 for a new ECM unless I'm confidant that it will actually fix the problem.

Do you have any useful information pertaining to this topic?

 

Yes, he did. But you appear to be too thin-skinned and thick-headed to "get" it. There's no reason to snipe back like that when someone is trying to help.

By reviving a long-dead thread from a long-gone member, you really achieve nothing, and the people with technical knowledge to share get dragged through a dead issue unless they carefully scan dates to keep from going down that rabbit-hole.

Better to start a fresh thread with your specific issues, and also look at toyota sites with the same engine and PCU logic/build.

 

OP is a 1 post wonder :-)

Any how, I had crazy error readings like this and found allot of wires frayed or shorted at the connectors. I found good connectors at the yard and re-spliced them. it cleared all the codes on it's own. Never came back. Just a thought.

 

It's not a dead issue for me. I understand that it is an old thread, but I have scoured the internet and found no solution. I have spent a lot of time on the issue and at this point anything is worth a shot. I am neither thin skinned or thick headed. I was pointing out that he was wasting his time by commenting on something with no useful information, and doing exactly what he was so against, commenting on a thread and keeping it alive.

 

Draco A50G what connectors did you find that were frayed or shorted? The only thing I have found was an aftermarket power lead on the positive terminal of the battery.

Thanks for your input.