Help please! Check engine lights on

[Budz]

Hello there, my car is a Verso-S 1.33 CVT.

I thought to clean the oxygen filter ( pic attached) so I have un done the switch ( whilst the engine was off) relates to it before attempting. But I couldn't get in to the sensor with my wrench so I gave up. I forgot to put back on the switch what ive un did and started the engine.

Now the check engine light it on! Ive then switched off the engine and connected the switch back on and started the engine but the check engine light is still on. 

Any idea how can I get thos sorted out please? TIA!

[Bper]

Hi Budz, Have a read through this article it may help to pin point the issue with the check engine light and the possible causes.

https://www.700r4transmissionhq.com/bad-oxygen-sensor-symptoms-toyota-verso/

[Budz]

39 minutes ago, Bper said:

Hi Budz, Have a read through this article it may help to pin point the issue with the check engine light and the possible causes.

https://www.700r4transmissionhq.com/bad-oxygen-sensor-symptoms-toyota-verso/

Thank you for your reply. 

I didn't had any problem with it in the first place but I thought just try and clean it. But I couldn't even get my hand in to the sensor. All I did was unplugged the sensor cable,  then start the engine to find the check engine light on. I did plugged back the sensor socket again as per the photo, but the check engine light didn't dissappear...

[Bper]

Are you sure you have plugged it back securely. You could try unplugging and plugging back again just in case.

You could also run a scan tool to see if any error codes are present.😄

[Budz]

21 minutes ago, Bper said:

Are you sure you have plugged it back securely. You could try unplugging and plugging back again just in case.

You could also run a scan tool to see if any error codes are present.😄

Yes, plugged in twice. Here is the error code

[Bper]

It could just be coincidence that this has happened but have a read of this it may help what to do. But It's likely the sensor is faulty due to age.

https://www.autozone.com/diy/diagnostic-trouble-codes/p0031-oxygen-a-f-sensor-heater-control-circuit-low-bank-1-sensor-1

[Perfection]

Disconnect the Battery and leave for 15mins and reconnect and see if the fault goes away.

[Perfection]

I used to own a RAV 4 and the oxygen sensor heater could fail. But the fault code you seen is more likely you had disconnected the connector and starting the engine. Taking out the sensor is a pain, but could be done, apply wd40 overnight to soak in then then warm the engine and try with a good special wrench for removing these sensors.

In the past for my RAV4, it used to fail every few years. So during 15 years of ownership, I mimicked the sensor heater with an external resistor to fool the ecu that the heater resistance is in range. I don't recommend this unless you know what you are doing.