Went to start her up and she sounds like a diesel and puked out all the coolent where do i start any ideas would be of great help.

03 140k miles oil changed a month ago, timing belt accessory belt water pump belt tensioner spark plugs and coil packs all replaced about a year ago all work done myself.

17862 - Exhaust Gas Temp Sensor 1 (G235)
P1454 - 35-10 - Short to Ground - Intermittent
17866 - Exhaust Gas Temp Sensor 2 (G236)
P1458 - 35-10 - Short to Ground - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 -
17870 - Exhaust Gas Temp Regulation for Bank 2
P1462 - 35-10 - Implausible Signal - Intermittent
17831 - Secondary Air Injection System; Bank 1
P1423 - 35-00 - Insufficient Flow
17819 - Secondary Air Injection System; Bank 2
P1411 - 35-00 - Insufficient Flow
16687 - Cylinder 3
P0303 - 35-00 - Misfire Detected
16686 - Cylinder 2
P0302 - 35-00 - Misfire Detected
16689 - Cylinder 5
P0305 - 35-00 - Misfire Detected
17869 - Exhaust Gas Temp Regulation for Bank 1
P1461 - 35-10 - Implausible Signal - Intermittent
16685 - Cylinder 1
P0301 - 35-00 - Misfire Detected
16688 - Cylinder 4
P0304 - 35-10 - Misfire Detected - Intermittent
16538 - Oxygen (Lambda) Sensor B2 S1
P0154 - 35-10 - No Activity - Intermittent
16725 - Camshaft Position Sensor (G40)
P0341 - 35-00 - Implausible Signal
16523 - Oxygen (Lambda) Sensor B1 S2
P0139 - 35-00 - Response too Slow
Readiness: 0000 0000
1 Fault Found:
18158 - Supply Voltage
P1750 - 35-00 - too Low

 

If you changed the coil packs, your ICM's are most likely bad. You should have upgraded to the 2.0 coils, and bypassed the ICM.
EGT's have boards the go bad. You can replace the board for about $40, replace the entire units for $500, or tune them out for $550.
For the $550, you can also tune out the secondary air.
I had this same list, did a 034 Motorsports Stage 1 tune, and had them tune out the SAI and EGT. No lights came back so far, and the car is a rocket ship!

 

Is there a list of "things you should fix when you get an allroad" anywhere?

I just got a pretty well maintained (IE by-the-book as written by audi in 2003) 2003; I'm having the shop do these things prior to me taking delivery:

1) do the timing belt / water pump / tensioner (current was probably changed 80k miles ago)
2) replace the PCV spider / valve cover gasket

what else should be done? It seems like the EGTs can go bad, but that's something that can be addressed when they go bad by replacing the electronics; is there an advantage to doing that proactively? Also, it seems like one (both?) of the radiator fans tend to explode; is the A4 retrofit documented sufficiently that I can just point the shop at this task as well? Or if the fan hasn't exploded yet does that mean that it likely wont'?

 

CDU - thats a really open question. Like all models, some can have very little issues and others just seem to be never ending problems, and the reason these sites are visited.

My experience - When you do the timing belt, replace the thermostat & housing, and replace the throttle body boot. I replaced the fan as it had some stress cracks, figured 11 years for the first one, if I still have it after another 11 years I can do it again!.

The other painfull job is the aux water pump mounted in the valley of the engine under the inlet manifold. Its not an overly hard job, just a pain to get to for what is essentially a simple bosch pump that could have been mounted somewhere else easier to get at.

I have a long list of parts i have replaced, but not much I can think of that I could predict would fail over another. Everything's coming up to 13 years old so stuff just starts to fail.

The best thing to invest in is something like the Ross-Tech VCDS (or similar). You can save yourself a lot of heart ache when you have a plug in device to point you in the right direction when the engine is not running right. better than guessing as parts are expensive if you start randomly replacing them in the hope of fixing a problem.

 

EGTs are expensive, It is not feasible to change proactively.

- In case you change the COMPLETE timing belt set (with water pump) I suggest to change the plastic water hose close to the TB (behind?) It is a flattened L-form 10 inch long fitting. This costs around 50 usd but the work to reach is enormous and the leak is very nasty if happens.

Motor top side:
In case you decide to demount everything:
- Aux water pump) as mentioned
- All rubber water houses around the aux pump! especially if they are oily
- valve gaskets and half moons (!!!) as well plus the actuator sealings
- plastic rails of the chain tensioners (if you see wear signs)
- pull out the injectors and cleansen in ultrasonic bath
- spider hose as mentioned
- Check viscous fan bearings and viscous coupling for function. If they are still good, I would let it but change the fan blades. 3 years ago did not change against the S4, because an OEM AR fanblade should be good enough for the next 10-13 years. BTW if you swap to the S4 system you should also change the visc coupling as well (3-screws or 4-screws fanblade mount) and the S4's fans are louder.
- Renewing the electric fan at the right side can be a good decision to change proactively if it is still the original.
- New Lambda probes (the front ones) for good mixture and MPGs independently from VCDS measures

Bottom side (at the firewall)
- Crankshat position sensor's cable can burn or melt if the external asbestos (silver) heat insulation "hose" had been removed by anyone. This can lead to sudden breakdown or unsure starts. If there is no insulation, change the sensor (if I can recall, they deliver a new insulation as well)
- my car's heat insulation shield (bottom, engine side and above the tranny in one big piece!) was damaged around the turbocharges, meaning the top layer of silver aluminium coating was not in place only the second layer beige asbestos and the bottom aluminum which connects to the car body. This is insufficient and it can lead to car fire on the highway. Check it. I bought a brand new OEM insulation, took 10 days to manufacture and deliver and cost 200 usd (in Europe) My engine and tranny was pulled out - it is needed to change this part.

Review
- all water hoses and decide on changing some of them proactively. They are relatively not so expensive but some of them are very hard to reach
- all airhoses. I changed all of them agains silicon ones. However it is a big amount of work and therefore quite costy.
- cooler at the front. Mine went wrong when it was 13 years old. Only the OEM with approx 42mm width will fit and it is really expensive. An option is a good used one.
- all rolling bearings at the front belt and especially its tensioning element. In case the latter one emits a very short "crack" or kind of scratching noise when you give some gas in D and starts to drive, it means it will fail in the coming year and should demount the front (again). If the front belt (to AC, generator, viscous fan, etc) is not tensioned properly, it can jump over/come free and ruin the plastic parts, cooler, fanblade, moreover according to my indy, it can have a rendezvous with the timing belt as well.

Air spring system
- Change the compressor's air drying set

 

mine had missfire codes in it when i bought it,never reocurred for me,but had constant egt and o2 sensor codes intermit for months.i changed a relay under the dash,as all these seem to be on same circuit so its implausable they all fail together,has to be power supply.all codes never returned.i also changed the battery to a high quality one as its important to have a powerfull battery to maintain power supply while cranking.i think the relay had 272 on it...cant remember as it was somr years back now