So I guess about 3 months ago, I got a P0327 code(#1 knock sensor). Hoping it was a fluke, I cleared it. A few weeks later, I got my DMV renewal papers in the mail, and tried to get the car smogged.

It couldn't be tested because the I/M tests for EVAP and Catalyst were incomplete.

Finally got the EVAP to complete, but I couldn't get the Catalyst to complete.

I would get an occasional P0327 and U0073. With these, the CEL would light, but then go out after a few key cycles.

I let my mechanic look at it to try to determine why the Catalyst test wouldn't complete. He said that both O2 sensors were right at the limit. Not failing the tests, but very close. He suggested replacing both, as well as the #1 knock sensor.

I have replaced both O2 sensors with OE parts, and replaced the knock sensor with a known good one from my old LNF engine.

I never had a code for O2 sensor, and the code for knock sensor has not returned. The U0073 has not returned either.

I also replaced the battery, as it was usually at 12.5 volts when I would test it.

While checking out my new code reader, I found a section that shows a bunch of test results. Every test was passed, except these 2.

June 21



And again today July 6





Now, I should mention that I also have been getting an occasional P0100 and P0102(MAF sensor). I cleaned the MAF sensor with the proper cleaner, and reinstalled. After some time, sorry, I don't know how long, at least a week? The P0100 and P0102 returned, so I cleaned the sensor again and reinstalled. This time I forgot to reconnect the harness, and was quickly met with P0100 and P0113. I reconnected the harness, and the CEL went out, but they both still show as current on my reader, it's been at least a week now.

I have ordered a new air filter.

I have completed countless drive cycles, and at least a dozen since replacing the battery.

This car passed smog 2 years ago, with the new engine, downpipe, and ECM. Between the last smog check and the aforementioned P0327, I had no issues.

 

https://www.obd-codes.com/p0327

Possibly a loose wire?

 

Purge valve?
I would suspect connections or wires to the MAF
I don't know what the fuel system thing is. Got a number?
I don't understand how there are "fails" without DTC. So why can't get smogged? What does I/M readiness say?

 

Purge says component ID $0c, fuel says $00, does that mean anything to you?

EVAP and Catalyst are incomplete.

The P0327 hasn't been back for quite some time. I'm hoping changing the sensor fixed that one.

 

The CEL has been off for at least a week, since reconnecting the MAF, but P0102 and P0113 still show as current. Those are the only codes.

 

;
purge valve is open. I think those numbers are PWM cylcloes.
The $00 and $0C are addresses on the CANbus

 

CEL has been off yet you are throwing present codes? How many starts since they set?

 

Can those addresses be translated to components?

 

Just ordered the purge valve

ACDelco GM Original Equipment 214-1473 Vapor Canister Purge Valve

 

I installed the new purge valve. I couldn't blow into either port of the old purge valve. First drive cycle, the EVAP testing completed!

Now hopefully that new battery will help the Catalyst test to reach completion.