05 STS P0430 (bank 2 cat efficiency)
Posted: Tue Jan 02, 2018 1:59 pm
My check engine light came on when I was running an errand this morning.
I had three guesses:
- Cat inefficiency
- Low engine temp (I think my thermostat is running the engine a little cold so I thought maybe it was taking too long to warm up to 195)
- Battery voltage (still sort of not sure about this charging system - it charged at a max of like 13.6 on a 15 degree cold start and eventually settled to 13.0 - that just seems so low to me)
Turns out it was cat inefficiency.
Now why did I suspect that? Two reasons:
1) There was a recall on 04-05 SRXs and 05 STSs both with the Northstar for premature cat failure (this code and a rattle), dated October 2010. GM doc ID 2551149.
2) I have seen a pending code for this when scanning with the Tech 2 on previous occasions but it never failed the tests enough to set a light.
More info:
The GM warranty extends for 12 years and 200k which is pretty generous. Not only is my car outside of that by a year, but according to the GM website, there are no open recalls on my STS. So it's either not a recall (which it may not be) or...only some cars were effected (in which case they would have traced to a supplier/batch).
Also, it has been quite cold recently so I'm betting that any kind of marginal cat performance would indeed fall on the side of failed in this weather. I have reset the code and I will see what happens. Not really excited about having to do this as I'll be fighting with cat to manifold bolts/studs/nuts for sure.
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)
So of these 7, the only one that is truly real in my opinion is the P0430. I did reset everything except the lumbar as I know that will come back the second I touch the switch again.
Hopefully my Marvel Mystery Oil treatment did not hurt the cat. It's been a few tanks since I did that so I think it's more the cold weather. I was thinking of doing another treatment actually.
Anyway, from here the plan is simple: drive until code comes back.
I was kind of surprised that when sorted by priority, the cat efficiency code was #5 out of 7. But I guess the first four are brakes and comms so maybe it makes sense.
I had three guesses:
- Cat inefficiency
- Low engine temp (I think my thermostat is running the engine a little cold so I thought maybe it was taking too long to warm up to 195)
- Battery voltage (still sort of not sure about this charging system - it charged at a max of like 13.6 on a 15 degree cold start and eventually settled to 13.0 - that just seems so low to me)
Turns out it was cat inefficiency.
Now why did I suspect that? Two reasons:
1) There was a recall on 04-05 SRXs and 05 STSs both with the Northstar for premature cat failure (this code and a rattle), dated October 2010. GM doc ID 2551149.
2) I have seen a pending code for this when scanning with the Tech 2 on previous occasions but it never failed the tests enough to set a light.
More info:
The GM warranty extends for 12 years and 200k which is pretty generous. Not only is my car outside of that by a year, but according to the GM website, there are no open recalls on my STS. So it's either not a recall (which it may not be) or...only some cars were effected (in which case they would have traced to a supplier/batch).
Also, it has been quite cold recently so I'm betting that any kind of marginal cat performance would indeed fall on the side of failed in this weather. I have reset the code and I will see what happens. Not really excited about having to do this as I'll be fighting with cat to manifold bolts/studs/nuts for sure.
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)
So of these 7, the only one that is truly real in my opinion is the P0430. I did reset everything except the lumbar as I know that will come back the second I touch the switch again.
Hopefully my Marvel Mystery Oil treatment did not hurt the cat. It's been a few tanks since I did that so I think it's more the cold weather. I was thinking of doing another treatment actually.
Anyway, from here the plan is simple: drive until code comes back.
I was kind of surprised that when sorted by priority, the cat efficiency code was #5 out of 7. But I guess the first four are brakes and comms so maybe it makes sense.