Car has no power. Data logged with VAGcom, only get 5.4 psi boost (1350 mbar abs) and torque capped at 235.2 Nm.

I have seen much higher numbers (particularly torque) before.

Is my car in limp mode?

Has codes:


17862 - Exhaust Gas Temp Sensor 1 (G235): Short to Ground
P1454 - 35-00 - -

17704 - Error in Mapped Cooling System (check Temp-Sensor and Thermostat)
P1296 - 35-00 - -

Pretty sure I need EGT sensor (bank 1 is passenger side I think), pricey.
Do I need pair or will one do?

Coolant gauge always shows 'fire hot', VAGcom reading is normal (60 deg C). What temp sensor drives the dash gauge and needs to be changed? How is it called (so I can locate the part) and where is it on the engine?

 

I think the coolant temp sensor you need to look at is the one in the lower coolant hose coming from the radiator. It is easiest to see from above. Passenger side of the radiator, you should see the sensor in the lower hose about an inch from where the radiator connection is. It is angled up and toward the center of the engine

Or maybe it is another coolant temp sensor. There is one on the back side of the engine somewhere IIRC but I'm not entirely familiar with that one

 

I know of the radiator temp sensor. Easy enough to reach (sometimes a bit hard to get out IIRC). How can I check if it is good or bad?

I know there must be another sensor, because VAGcom takes a DIFFERENT reading (and currently shows different values), so must have another sensor.

Which one turns the electric fans on?

 

The coolant temp sensor controlling the gauge at the pod is the one behind the motor. It is located in the cross pipe behind the passenger side head. It is pretty straight forward replacement, and shouldn't take more than 30 minutes. You may want to try that before messing with EGT sensor. Be sure to order the o-ring as well has the plastic holding clip.

 

Just noticed the power steering fluid is low (may even have a leak on the rack?)
Audi is using synthetic and non-synthetic mineral power steering fluid. As usual, they have their own fancy stuff.

Considering that most cars run well even with transmission fluid as their power steering fluid:

Is it critical ('a must') to use the fancy Audi stuff (for example Pentosin), or will 'standard' fluid do just as good?

 

I would stay with the mineral oil. It is not that expensive and hard to find. Pentosin CHF 7.1 to be exact...

 

Picked up 2 liters (synthetic, not the CHF 7.1 but the 11.1 or so): $40!
I call that EXPENSIVE.

Particularly, since in my case with suspected leak (in steering rack maybe), it may just leak out in no time.

AND: no guarantee that some previous owner no already 'topped off' (think: quicklube: we top off all your fluids) may have already done the big no no: mix!

In this context:

Coolant: the standard 'green' stuff is PERFECTLY good. Only difference: the super duper VAG stuff is good for 100k, while the normal stuff probably should be changed every 40k. But also here the big NO NO: DO NOT MIX.

Transfluid: you actually can mix. But if just topping off, the real stuff is ok costwise. it gets really expansive if a complete change is need. I changed trans, and THEN the cost difference is huge; went with good 'standard' stuff.

Oil: Obviously: Synthetic a MUST on any turbo motor! No exception. Since the classification for 'full synthetic' was 'relaxed', a lot of oils now can call themselves 'full synthetic', with only a few 'true synthetic' left.

I have decent availability in my area of 'Mobile 1 European Formula' and Castrol (also called GC for German Castrol) with their "European Formula" and 'made in Germany' on the back (both true synthetic meeting even the old, more stringent specification'; if on sale, $7/quart or so. On my stock turbo cars, I run a good standard (Mobile 1 for example) synthetic.

Oil filters: check the specification of their bypass pressure. Seems your Fram, etc. may NOT meet the required bypass pressure (1.8T/diesels specify 2.5 bar (W940/25), 2.8/3.0/2.7T specify 3.0 bar (W940/21). My stock turbo cars also get standard Mobil 1 filters (strange: often more expansive than the Bosch). My 'tractors' (low output NA cars: FRAM) and non synthetic oil.

 

That mineral oil is a lot cheaper than Grey Goose. I guess everything is relative.

 

Best way to drain the power steering unit (engine currently not running), before filling fresh good stuff in ?

 

they are currently discussing power steering pump problems in the "bucket list" thread. I like Jeremy's (ImTheDevil) idea of disconnecting a line from the power steering pump and using a cordless drill/driver to spinning the pump to pump out the reservoir (serp belt off, of course)

I'm sure you could PM him for details.