Codes 63, 13 and 31

[RICHARD TILL]

Thanks in advance for any advise or comments. Several months ago i had a intermittent code 63 which is the right oxygen sensor. I swapped that sensor to the left side and got code 13 . Yesterday i replaced the left sensor with DENSO 234-3094 that i purchased from Rock Auto. Supposed to be an exact replacement. As soon as i started the engine the service engine light came on. This time its code 31. I have the ST-364-90PSID manual and it states that its the cam sensor. The manual said to probe ECM harness pin D3, crank the engine over and read the meter. Big mistake i guess but i didn`t do that. Gotta dig and find which wire on the brown connector D3 is. I skipped to connecting a test light between terminals A and C of the supply side of the connector to the cam sensor. The test light did light up and instructions say that its a faulty connection or bad cam sensor. My connection is good. I know that i need to go back to the first test procedure but heres the tricky part. Just for the heck of it i reconnected the old oxygen sensor, left it hanging loose, started the engine and didn`t get an instant code 13 like i did before. How could that be? Could a wrong or faulty new sensor cause this?

[GOLDCYLON]

Did you clear the codes after the install of the O2 sensor? IF you didnt you still might have a code retained. Just an idea

[XfireZ51]

Clear the codes first. See which one comes back. Interesting you're getting both O2 sensor codes.

[RICHARD TILL]

I`m not getting both codes now. Only get code 31 when the new left side oxygen sensor is hooked up. To clear the codes i unhooked the battery terminal for about 30 minutes, reattached and observed code 12 with no others.

[XfireZ51]

I`m not getting both codes now. Only get code 31 when the new left side oxygen sensor is hooked up. To clear the codes i unhooked the battery terminal for about 30 minutes, reattached and observed code 12 with no others.

Are u using an extension?

[RICHARD TILL]

Extension? I don`t think so but i`m not sure what you are asking.

[XfireZ51]

Richard,

You have headers? To clarify, what codes do you currently have? Did u change O2s w battery connected?

[RICHARD TILL]

No headers. The car is bone stock with 121k miles. I immediately get the code 31 after starting the engine. No codes with the old oxygen sensor connected and hanging loose. Front of car is on jack stands. I never do anything electrical without disconnecting the negative battery cable.

[scottfab]

No headers. The car is bone stock with 121k miles. I immediately get the code 31 after starting the engine. No codes with the old oxygen sensor connected and hanging loose. Front of car is on jack stands. I never do anything electrical without disconnecting the negative battery cable.

Battery connected won't matter.

Something's just not right. O2 sensor causing a CSS error?
Clear you mind.
Start over.

Clearing codes only takes 10 sec. No need for 30min.
How are you reading codes? Counting flashes?
Redo and recount. Remember 12 is at the end of all
before it repeats.

When replicating the 31 and reconnecting the bad sensor
to see the 31 go away make sure to then connect the new
sensor back up and see the 31 come back (so called capping run)
Puzzles are meant to be solved