Sid2020

This picture was taken from the b9 forum and if your a3 has similar design it would allow coolant to flow in and out of the matrix but if the water ways are blocked you would get no heat transfer into the cabin as it needs to travel thru the water ways for that to happen

I don’t have access to the Audi coolant schematics but typically the water pump circulates coolant around the engine block, turbo if water cooled, egr cooler and any other heat critical parts and the matrix for occupant comfort. Only once the coolant reaches a certain temperature does the thermostat open and allow coolant to flow from the pump into the radiator for cooling. To remove air fully the system must be upto temperature so the thermostat opens and allows the flow around the complete coolant system and allow trapped air to be pushed back to the reservoir

Be worth checking the turbo oil feed pipe isn’t leaking where it fixes to the top of the turbo core. This pipe will have a fair bit of pressure in it when engine is running so worth checking with engine on and off, oil loss can be very small as it is often a weep rather then it pouring out

Steering will be electric so any problems with charge system or battery can affect the steering as it consumes a lot of current. Your Clutch is purely a hydraulic system apart from a sensor which is there for the start and cruise control systems

The cam shaft sensor fault if it’s only occurring once the engine is warm I would be inclined to say the sensor is starting to fail when warm so simply replacing it would be with a try. Your flow fault depends on on your exact engine type but commonly is a fault generated when the 2 coolant temp sensors give differing readings over a set time frame which the ecu thinks is abnormal. Could be a failing water pump, thermostat, either or both temp sensors or wiring issue. Live data displaying both coolant sensor temps would be worth a look

Is the slave not in the box on the c7 so massive job, I’d try master and bleed first as simple to change and if that doesn’t fix then box off and slave and clutch while in there

Sounds like what I had, I changed my master cyclinder and gave it several bleeds using Comma Dot 4esp brake fluid, I used a pressure bleeder as a lot easier. Don’t use standard Dot 4 brake fluid, a mistake I made first time round

I would be inclined to say it sounds like a hydraulic problem, are you losing brake fluid, does changing gear get easier after driving for 10 minutes. If car left for a few days does it get harder to change then usual.

74 and still tinkering, your a legend in my eyes terry

I came to the understanding after sitting thru many training courses that the manufacturers have to juggle giving customers a car that drives good but one that is also reliable and will last well past 100k. Cone filters, blanking egr’s and mapping can be fun but ultimately puts more strain and wear on other components.

Glad you got it fixed

Turbo lag when is when your turbo is not spooling up at the desired rate due to a lack of exhaust gas to spin the exhaust turbine, typically being in a gear to high and planting the accelerator will produce turbo lag until the revs pick up enough to produce more exhaust gas to spin the turbo to provide the boost required. Your turbo will be spinning as soon as you start your engine due to the above reason and will increase in speed with more revs.

If it’s second hand then they have component protection on them as tried several years ago to use a second hand one. I think the only Real option is either get a garage to remove component protection and recode it or new from Audi and code it in. Ain’t sure about a individual fuse for multi function wheel

I would suspect that Audi sold them as an accessory kit so wouldn’t have individual parts numbers and sometimes are not available for long. Have you looked into getting your existing trims carbon hydro dipped as the results are very impressive

Steering angle sensor usually comes as a complete unit with the storks and the multi function steering wheel and airbag plug into it. Has the correct part number been fitted as quite a lot or variables. Has the coding been done correct. Have they crushed the loom inside the steering wheel when reinstalling the airbag. Anyone that replaces this without disconnecting the battery shouldn’t be allowed near a car and are lucky not to be picking there teeth out of the airbag.

These are from a A1 1.4 tfsi that I did a few weeks ago so if any of it looks familiar then this is what you may also have

I believe what I’m seeing is the combined water pump and thermostat but hard to tell from the picture. The crud could also be from a additive that someone has added to seal a leak

Are they the only 2 faults on your whole car when you run a full scan

Disconnecting the battery resets the cars computers so it may have been deactivated in the mmi. It may be a case of having to climb under the rear bumper and removing the fixings so you can pull it down and access the sensors and control module for the comfort opening, check for corrosion in the plugs and wiring and any visual damage Incase it’s had a rear end shunt at some point. I see the photo of the fault codes had a live data section, this could prove handy while checking the connections

Sounds like a motorized flap may be jammed/broke on the heater box. When you say the matrix was changed I presume just the radiator not the complete heater box

Try locking your car and waiting a few minutes and without your keys go out and see if you can open your tailgate. Just Incase the module isn’t powering down or your key is in range overnight. Always worth ruling out the simple and random things

That explains the 2 fault codes. Do they come back if cleared now it’s working. Trying to think of how that sensor or controller would trigger your alarm or what to try to find out. Unplugging it is one way, is there an option in Mimi to deactivate it.

Your first post says you’ve had this problem since you’ve owned the car so maybe you do have it and it’s never worked and that’s the fault, the sensor wires are usualy on the underside of the rear bumper spoiler fixed into location brackets

Do you have comfort access where you can wave your foot under your rear bumper as the fault codes your getting are not what I would expect to see for a glass sensor

I would try disconnecting the blue wire plug and using a small length of wire with the ends stripped off or a unfolded paper clip to make a jumper wire for the plug on the tailgate loom and see how you get on, clear the faults and see if they come back