P0135 P0155

Good evening.

The codes do not indicate any issue with the sensors. I will post possible failures for you for each code. Codes never identify bad parts just failed systems.

Roy

1132

Okay, the other codes are all related. Possible causes are below.

The issue is electrical from the looks of it. Check the items listed. Make sure you check all the fuses for power on both sides with the key on.

Check the harness for any damage on all sensors.

Roy

P0135 - Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 1).
P0141 - Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2).
P0155 - Oxygen Sensor Heater Circuit Malfunction (Bank 2 Sensor 1).
P0161 - Oxygen Sensor Heater Circuit Malfunction (Bank 2 Sensor 2).
P1132 - O2 Sensor Heater Control Circuit (Bank 1 Sensor 1)

It is possible for one of these fault codes to set due to a defective oxygen sensor, but that would be the least likely thing on the list of suspects. Once a second code for the same thing shows up, we know we need to look for what they have in common, similar to all the head lights and running lights fail to light up at the same time. You would not suspect every bulb burned out at the same time.

In this case, ...

Part 2:

Hi Roy. That is what I typed last week, but I stopped once I looked at the wiring diagram and saw all the other stuff on that circuit feeding the O2 sensor heaters. There are dozens of other things that would not work if there was a problem in the 12 volt feed side. To add to the misery, it looks like the engineers could not just run one wire, then split it to feed all four sensors. It appears there are splices all over the place, with the O2 heaters tapping off in various places. That means it is unlikely anything in the 12-volt feed side would affect all four sensors.

The last thing on your list is the Engine Computer, and in fact, all four sensors' ground circuits go into it on four separate wires. All four sensors are tied together on the 12-volt side, so there cannot be any monitoring on that side. There are four individual ground returns to the computer, so those have to be where current flow is monitored. Is it possible there is one part of the circuit in the computer that is common to all four grounds, and that is what is causing all these codes? I have not read much about computer failures related to this, but it seems like the logical suspect. I do not have an answer, but I figured you would love my great and wondrous wisdom! I never have faith in my diagnosis of a defective computer until I actually see the problem is solved.