Check engine soon lite?

[helicopter23]

It came on, can someone explain to me where the oxy sensor is, (97 Grand Prix GT) last time it came on it had debry on it.

[BNaylor]

There are two 02 sensors. One located before the CAT converter and one after. The pre CAT is located on the downpipe and rear exhaust manifold area close to the firewall. The post CAT located right after the CAT in the u-bend section of exhaust pipe but before the resonator if you are stock with no exhaust mods.

What is the code (DTC)?

[helicopter23]

Originally Posted by BNaylor

There are two 02 sensors. One located before the CAT converter and one after. The pre CAT is located on the downpipe and rear exhaust manifold area close to the firewall. The post CAT located right after the CAT in the u-bend section of exhaust pipe but before the resonator if you are stock with no exhaust mods.

What is the code (DTC)?

Have not gotten a code yet. What are usually the main problems? Last time it was the oxygen sensor had a piece of debry on it.

[BNaylor]

Dirty with carbon or some other debris/contaminant. Without a specific DTC hard to tell since there are several 02 sensor DTCs that could be set to trigger the check engine light.

[helicopter23]

I got codes P0135 oxygen sensor B1S1 heater circuit P0401 insuff. EGR flow code. They clleared all codes. Can any of these 3 codes something I should be worried about in the future?

[BNaylor]

DTC P0135 means there is an issue with the heater circuit for the pre CAT 02 sensor. The next is an EGR flow test failure. Check your PCV valve and make sure it has the black o-ring. Both are concerning so you should get them resolved if the DTCs return along with the SES/CEL light.

[helicopter23]

Originally Posted by BNaylor

DTC P0135 means there is an issue with the heater circuit for the pre CAT 02 sensor. The next is an EGR flow test failure. Check your PCV valve and make sure it has the black o-ring. Both are concerning so you should get them resolved if the DTCs return along with the SES/CEL light.

So nothing to worry about unless the check engine light returns, correct?

[BNaylor]

I don't know if there is nothing to worry about for now, however, nothing much you can do until they return. If the DTCs return it will just confirm what you already know and then time to take corrective action. Good luck!

[helicopter23]

The check engine soon light has NOT come back on yet. I checked an old code I had clear about 10 months ago which was 1406 EGR pintle position, could that be related to the previous codes I just had cleared?

[BNaylor]

Thats good. Until the SES/CEL light comes back on not much you can do. I wouldn't worry about an old history DTC dating back that many months unless it comes back.