b16a2pwr

oh no. that doesnt sound good...

CrazyMoparGirl

12 is Battery Disconnect
21 is one of three 1) Upstream o2 Voltage shorted to Ground 2) Upstream o2 sensor shorted to Voltage and 3) Upstream o2 sensor slow response.
More detailed info: 1) tested after key off and at start run
2) Upstream O2 sensor input voltage maintained above normal operating range
3) Upstream O2 sensor response slower than min required switching frequency or value does not go above .65v

Baisically replace it IMO

CrazyMoparGirl

Sounds like my old Neon O2 came and went till it went for good N/p anytime and your welcome

CrazyMoparGirl

if the car is cold 20min with an O2 sensor socket but if you wanna make yourself work faster get the car to operating temp first









j/k

CrazyMoparGirl

We had to borrow Walters O2 socket

Here are the directions straight out of the SM
1) Raise and support Vehicle
2) Unplug Sensor Connector
3) Remove Sensor using crow foot wrench or equivilant
4) After removing sensor the Exhaust Manifold threads must be cleaned with an 18mm x 1.5+6E tap coat new sensor threads with anti-seize.
How to install
1) Install sensor and tighten to 20 ft. lbs
2) Plug sensor to connector
3) lower vehicle.

It is the O2 sensor before the cat closest to the engine. near the exhaust pipe flange.

CrazyMoparGirl

I think it cost me about $90 at One Stop but I could be wrong.