crazydad1

I need this monitor so I can pass the NYS inspection. (The evap one has never set ready and NYS says you can only have one not ready monitor) Car is a 2002 SS 6 spd with SLP Exhaust and intake.

Replaced all the O2 sensors as they had almost 100K on them. Checked the voltage when engine was cold with the key turned to on position but car not started. Ground wire is good. 12+ volts on power. Other wires read @5.3 volts and 4.9 volts.

I don't want to tune them out as I suspect at least one cat is going and I want to get it replaced under the GM TSB. Any help or suggestions would be appreciated.

Thanks,
Steve

NoGo

iTrader: (2)

Help me out. OH monitor?

crazydad1

One of the monitors for the OBD II system that they used when they do inspections. It also keep strack of the diagnotic trouble codes (the things that cuase your SES light to come on.)

NoGo

iTrader: (2)

I'm guessing your are showing an O2 not ready or CAT not ready code in addition to your EVAP readiness check?

If it is a CAT not ready, you need to put more drive cycles on the car (ie. just drive it around town for a few hours) before taking it in for inspection, or you need to change your CATS. If it is an O2 not ready code then you either need to put more drive cycles on the car before taking it to inspection, or you should be throwing and additional O2 related SES code (insufficient switching, etc...)

FWIW, Evap is usually an old gas cap or purge valve....both are pretty easy to change.

crazydad1

No codes at all. I wish it would throw one to help me diagnose this. Just will not set the monitors ready. I know we haven't done enough drive cycles for the CAT monitor to set. Supposedly this test won't run until the O2 monitors have run. What's weird, though, is the last time this happened, even though the Oxygen Heater monitor wasn't "ready", the Cat monitor ended up completing. This makes me think it's somehow running but just not reporting so on the PCM.

I need to check if the PCM thinks the key is somehow in the ignition. The first part of the GM drive cycle says "Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run." Maybe that's my problem.

I was hoping someone would say check for bad pin, loose wire going into PCM or something like that. So far I haven't seen any loose wires but I there's a billion wires going in there so I have no idea if I'm looking at the correct ones.

NoGo

iTrader: (2)

If you have LT's and have relocated the O2s away from the engine you can cause issues with the O2 readiness on the heater end.

Any mods?

crazydad1

None other than the factory SLP intake and exhaust and the OH monitor used to set with those.

NoGo

iTrader: (2)

You got me.

If the O2's have been replaced and the heater voltage looks okay and you have put drive cycles on the car then I don't know. It should set a ready.

Is the car getting up to temperature? Do you have bad thermostat or RTD in the head. If the car isn't showing up to temp it may not try and switch to closed loop, at which point, I don't think it would start the O2 test - and thus would show a not-ready even though everything is fine.