Replaced O2 sensors still getting PO135 and PO031?

Hi,

The P0135 is resulting from the P0031. You have a short to power at some point in the wiring or the PCM.

The first thing I suggest is to disconnect the new sensor and inspect the connectors for damage, pins that are touching, and anything that can cause a short.

Next, with the sensor connectors disconnected, with the key on, check the voltage to the sensors using a voltmeter or multimeter. If you have battery voltage, disconnect the battery negative and then the PCM harness. Reconnect the battery and check for voltage to the connectors again with the key on.

If there is voltage, we have a short between the module and sensors. If there is no voltage, check the PCM connector for damage. If none, chances are the problem is the module. Note: Before reconnecting the PCM, disconnect the battery. Once the PCM is reconnected, then you can reconnect the battery,

I added additional tests below. Also, pic 1 shows the definitions for the codes you have. I thought you may have an interest in seeing them

Let me know what you find or if you have questions.

Take care,

Joe

See pics below.