P0138 after blower motor resister change

Went to change the blower motor resister because of the common no fan on low settings issue and got a P0138 upon startup.

Is it coincidence or related because I didn’t disconnect the negative terminal on the battery.

I googled and it seems P0138 has to do with the O2 sensors. I don’t have an advanced scanner to dive deeper yet. Any advice?

Thanks

05 TRD DCLB 155k miles

 

I disconnected the battery and let it set for awhile. Turned it back on and the CEL hasn’t come back but now it’s running rough/vibration and idling low rpm below 500 rpm as if it would stall at any minute.

I did change the plugs a month ago and has been running fine until I changed the blower motor resister.

 

Changing the blower motor resistor will have no affect on O2 sensors or the CEL.

If the battery is disconnected long enough the ECU will forget all of its fine tune settings. It has to be driven to relearn those settings.

 

Drive it and it will relearn the idle...

 

I agree.

Clear it, drive it, and see if it returns.
That the is first steps of the simplified version of the diagnostic flow chart.

 

Yea I did some further googling and I just leftthe car on for about 10 mins and it returned to normal.

The CEL has not returned either. Fingers crossed.

thx