Finally solved the Check Engine Light (1221 code)

[Erick]

I'm dumb.

I replaced the O2 sensor with one of the Bosch Universal O2 sensors - which involved cutting and splicing the existing 4 O2 sensor wires.

But I STILL got the check engine light with 1221 code. :(

It took many months, but I FINALLY figured out the problem...

I'll cut to the chase --> the connector in the engine compartment (drivers side by starter) that connects the O2 wires to whatever, wasn't FULLY connected. I gave it a little turn, and to my surprise, it clicked into place.

No more CE light!

:embarassed:

Erick

[edit: My gas mileage went from 14 to 17 mpg after reconnecting.... :) ]

[AllanS]

Were you getting a constact check light, or would it chime on once in a while and go away? Either way, that's cool that you fixed it, even though you bought a new sensor :P

[Erick]

Allan,
The check engine light would always come on once the car reached normal operating temperature. No chime. The only code registered was the 1221.

Erick