I first got the P0410 (secondary air injection system)and P0175 (system too rich - bank 2) fault codes but there was no CEL but a day or 2 later I got a CEL and rechecked the system and the additional P0128 (thermostat)code popped up. My question is, are the first 2 codes related to the thermostat fault because the ecu is trying to compensate for the cooler temp of the engine. I bought a new OEM thermostat which I will be fitting in the week so I'm wondering if that would rid the other codes as well or is there an additional problem elsewhere. I read that the secondary air injection systems are prone to relay problems as well. Hoping the thermostat change will sort all the fault codes out.

bump

I had the same problem last winter. Replaced the tstat and she's all good now.

hum... not too sure the thermostat fault code is related to the first 2.
Secondary air pump is used at cold start up for about 30s as the air/fuel mixture is too rich. So having a faulty pump would generate that rich condition. Which IMO has nothing to do with the coolant thermostat.
Also the secondary air pump fault could simply be some condensation due to cold weather and short trips. Hence the CEL disappearing after 2 days. I see you are in South Africa so winter coming your way

Thanks Jasonoff and abcut973 for your feedback, fortunately Jasonoff was right, had the thermostat (and serpentine belt) changed today and no fault codes on the ecu.


You can see right through the seal at the bottom, shows no water was held up and all recycled preventing the engine not to warm up properly.




From a different angle.

That thermostat must have been on there since the motor was built (08), the vehicle is on almost 140000 km (87000 miles). Hope this info is useful for someone else in future

I had ~90k km on mine when it failed.

Nice 140,000 km, how does she run otherwise?

I have a p0128 aswell.
How dificult is it to change the sensor?
How easy is it to change the thermostat?
Also, do you have part numbers?

Cheers

Sorry just see this now. car drives like a dream. Have never topped up oil before.

Oil consumption is not bad and expected; from the owners manual:
Depending on your driving style, the vehicle consumes up to 0.9 US qt (0.8 liters) of oil per 600 miles (1,000 km).

I've never personally seen it that high, but in the summer when I drive more spiritedly, she definitely consumes oil. About 1 US Quart every 5000 km.

Lol, so ironic. On my second c63 now and thermostat is busy going, giving me secondary air codes again and did a search to see if they are related just to come to the only thread on the search which is mine from 3 years ago. Who needs a memory if you can search