Just so there is a little more clarity around acronyms since it is taking on a more important role in this thread. If you're discussing a fault related issue with any tech, they'll use ECU or ECM to discuss the actual physical unit that manages all of the engine functions.

If you go to the "book of acronyms" regarding computer management of ICE cars, the first interpretation of ECU is going to be Electronic Control Unit. In this case, ANY control module found in a modern automobile is going to be called an ECU. Once you're off the top level of the acronym pyramid, then each module has it's own specific name and acronym.
ECU/ECM = engine control
TCM Transmission control
BCM body control
etc.
PCM is sometimes used as well, as yet a third name for the engine control unit - Power train Control Module. Techs mostly use ECU, sometimes ECM, rarely PCM, but they mean the same thing, the physical computer control unit managing the engine functions.

 

Thank you.

The information you've provided helps reduce the mystery.

Thanks to Mr. Ing. Green and his admonition I checked and rechecked the gas cap. It was ok.
I'm intrigued by the comment about the icon coming on as a cyclical/life cycle event (the Service Now icon had been on for some time since at the
last service, the shop didn't reset that warning. It's a long shot but maybe that triggers the check engine icon after a prolonged period?

I should know more Monday.

 

Internal Combustion Engine
In Car Entertainment
Improved Control and Efficiency (I kid you not).

Not trying to muddy the waters, just hoping to demonstrate to the OP that context is everything and not to get *too* hung up on what a acronym or initialism might actually stand for....

Can't see any reason the CEL (check engine light, also called the MIL, management information light) would be triggered by a failure to reset the service light.

The estimable @BWings may no better but to my understanding that little orange light only lights with something that will detrimentally impact emissions.

C

 

I get it. But other than an obvious mechanical defect, how can a shop/hobbyist ever trouble shoot the orange icon?

 

Practice, and it depends

C

 

The check engine light is gone for the moment. 3 of the 4 fault codes were cleared. The
remaining one is P0546cc exhaust gas temperature circuit bank 1 high.

I will get the car back on Monday and hope for the best. The car always runs beautifully, new
factory batteries were installed 6 months ago (the original 2012 dated batteries were
still functioning but probably approaching end of life on this 2013 GTC). I bought it
in November, 2020, with 14,000 miles, now at 16,400, and no problems til now except
for two hinges needing tightening so that convertible top wouldn't stop at half mast.

This has been a crash course on the innumerable electrical issues I've read about on this forum.

 

The EPA as well as all the other world's environmental government agencies agree with you....as do I. Anything.....and I mean anything that fails to operate, as designed (and whose design was emissions certified by these organizations), on an internal combustion engine fails to meet the original emissions standards...which sends the EPAs of the world in a tailspin. It is those groups that insisted on these OBD check systems in the first place and what really drove the design.

If an engine is misfiring and only running on 11 of twelve cylinders, is there a doubt that engine is meeting the same emissions standards as one running efficiently on all twelve? Or, put another way, can you look at the list of P-codes for a VAG engine and pick one (any one) that would not lead to an impact on emissions?

Now that the EPA is out of the way, we still have to fix a failure that the "system" picked up and identified as failed as that orange light is disturbing to stare at for any length of time for most of us.

 

Totally agree!

C

 

This part is on order from Flying Spares for my intermittent fault code described previously:

07C919529K
1
£314.99
£314.99
^ EXHAUST GAS TEMPERATURE BANK 1

Of interest, the local dealer's price for the part was over USD $800, and of course the Bentley dealer recommends replacing both banks.
After it's in place I will post a follow up.

 

Glad to see you on a path to recovery. Hope you do follow up when all is well.

On the positive side, it must be a load off your mind that your gas cap is OK.....

 

Actually, I have to confess rather than spending on labor to trouble shoot the sensor,
I've decided to replace the sensor expecting that will solve the problem (failing sensor, intermittent
in the cable, etc.). My understanding is that the bank 1 sensor is pretty easy to replace, not so
easy to troubleshoot. I am deviating from Bentley guidance and NOT replacing both sensors at
the same time, as I 'm using an independent garage.

I hate to capitulate to just replacing the part rather than diagnosing, but the labor cost makes
it more desirable to throw in the towel. Hopefully that will fix the problem.

The part is in transit from FlyingSpares. Half the price of the local Bentley dealership.

 

One of our members here Eapplebaum is very good at these exhaust sensors. There are a couple of different repair strategies if you're working on a budget. Rather than typing those out, maybe consider reaching out to him.

 

Hi Guys,

Attached is a good write up re:EGT sensor repair. Email located in attached article: Sid Motor Sports. Indicate a EGT repair module for a BGT. Cost is about $60.00.

E

https://www.audiworld.com/forums/2-7...-good-2850845/

 

I received my new sensor from Flying Spares and will have it installed next week.
Is there any compelling reason to replace the bank 2 sensor at the same time?
I've read a couple of advisories to replace both sensors at the same time, but
I can't really see why.

 

These sensors "wear". They are less on/off than they are varying grades of effectiveness. Replacing both is better odds that both banks stay in balance. Same happens with O2 sensors which are very important to the EMSs fueling management. Once one O2 sensor gets "lazy" (more frequent) or fails completely, the second one might not be long for this world.

THEN, there is the "keep it running at least cost" philosophy. Given the cost of these (and one is much harder to replace than the other) you might find yourself running the dice with just one replaced. THEN, there are those who figured out how to send the signals from one side, over to the failed side thus avoiding replacing either sensor.

Here again Eric is the man who knows these routines (from my experience).