05 STS P0430 (bank 2 cat efficiency)

[kevm14]

No light yet.

[kevm14]

Light still off. Did some pretty good hammering this morning.

[kevm14]

More hammering last night. No light.

Though I will say the heavy to WOT 3-4 shift leaves something to be desired. It seems a little sloppy/delayed. Not sure if there is a TCC lockup happening after the shift that makes it feel funny to me. Possibly.

Funny anecdote: I saw a broken valvespring thread on the forum. I've never heard of that on a Northstar (82k). One guy chimed in saying the #1 cause is acid etching from super short trips (oil becomes acidic and moisture-laden). I just thought that was funny because between that and people notoriously driving these engines too lightly leading to ring sticking, it is just more evidence that these engines need to be exercised.

[kevm14]

Still no light. Ran my tank with MMO nice and low....

[kevm14]

I didn't drive the car at all last week but I thought I'd mention the light is still out.

[kevm14]

Light still has not come back. Almost 6 weeks. We are well past the minimum amount of time between diagnostic failures where I could reset the light and be able to drive the car enough to ready the systems to pass a plug-in test. So at this time, I think this is a non-issue. Curious how long it'll actually go.

[kevm14]

My check engine light came on when I was running an errand this morning.

Anyway, from here the plan is simple: drive until code comes back.

It came back Saturday night (2 months almost to the day). I remote started the car while walking up to it and the light was on before I got home, and it is a very short drive (6 mins?) from where it was parked. It did not warm up fully before parking. I think all of this is related. My memory is hazy but when it came on last I think it was in similar conditions (had either just made this same drive, or was about to...). Anyway, I reset everything again and it did not come back on my commute.

I do think my thermostat is hanging open a little and not letting the car warm up as fast as it should. I may elect to change that. It could also help this cat situation.

[kevm14]

Other fun facts:
When I actually scanned the car, there were 7 codes present. Only the cat code P0430 was requesting the MIL. Here are the six silent codes it had:
- EBCM C0250, symptom 71 (unknown DTC, history code, possibly triggered by Tech 2 as I had a Service Stability Control message as soon as I started scanning)
- EBCM C0249, symptom 71 (unknown DTC, history code, same as above)
- Instrument Panel Module U2100, symptom 72 (CAN bus communication alive counter incorrect/not updated, history, possibly same as above?)
- Instrument Panel Module U2100, symptom 00 (CAN bus communication, history, same as above?)
- Driver Position Module B1850, symptom 58 (Seat lumbar horizontal position sensor circuit incorrect reaction after event, failed, also my lumbar does not work and I've seen this code the entire time I've had the car so it is old news but including here for completeness)
- Driver Position Module B1850, symptom 08 (Seat lumbar horizontal position sensor circuit signal invalid, failed, see above)

Scanned it again. P0430 cat low efficiency bank 2, as predicted. Also, I had the following "silent" codes like last time (despite resetting all):
- Instrument Panel Module U2100, symptom 72 (CAN bus communication alive counter incorrect/not updated, history)
- Instrument Panel Module U2100, symptom 00 (CAN bus communication, history)
- Driver Door Module B3849, Symptom 02 (Exterior door handle switch circuit short to ground, history)
- Driver Position Module B1850, symptom 58 (Seat lumbar horizontal position sensor circuit incorrect reaction after event)
- Driver Position Module B1850, symptom 08 (Seat lumbar horizontal position sensor circuit signal invalid

I don't know what the U2100 is all about, unless it is tied to the B1850 "invalid signal" which may very well be the case. The B3849 is new and I have started having issues with my driver's door actuator though it has been fine for a while. This is very common and is usually a microswitch issue in the handle (a little PITA but cheap to fix DIY), but can also be the antenna in the handle. I will wait until it gets worse and this isn't the thread for it anyway.

But I am a little bummed that my cat code came back in 2 weeks. With the warmer weather (and new stat) I am hoping for longer. On the other hand, the new stat warms the engine up quicker which actually lets it run the diagnostic sooner in the ignition cycle which, ironically, may be with a COOLER cat temp (engine coolant temp does not directly equate to cat temp). That would figure, if true.

[kevm14]

Randomly mentioning that it's been fine, no codes. Or I should say, no light. It probably has those silent codes still.

[kevm14]

I totally jinxed myself.

Came on this morning after about 4 minutes of driving. I reset it with my generic tool.

I did remote start it this Monday. A repeat correlation.