heavykrush2

Gents,

Pulled the following codes from '04 2.7T S-Line. I can find info on each code separately but wondering if all the codes together point to a common problem? Any help would be greatly appreciated.

17887 - Brake Boost Vacuum System: Mechanical Failure
P1479 - 35-00 - -
17965 - Charge Pressure Control: Positive Deviation
P1557 - 35-00 - -
17861 - Exhaust Gas Temp Sensor 1 (G235): Open or Short to Plus
P1453 - 35-10 - - - Intermittent
17521 - Oxygen (Lambda) Sensor; B1 S1: Internal Resistance too High
P1113 - 35-10 - - - Intermittent
17537 - Fuel Trim; Bank 2 (Mult): System too Rich
P1129 - 35-00 - -
17535 - Fuel Trim; Bank 1 (Mult): System too Rich
P1127 - 35-10 - - - Intermittent

Just Me

Yea, maybe an electrical problem either causing some of the underlying issues or crating false reports. Ground, regulator, weak battery....

heavykrush2

Decided to run down the brake booster first. Can't seem to locate the fuse? Seems it's located on the "auxiliary relay panel" but I have no idea where that is located?

heavykrush2

Found it. It's under the steering wheel. Also found that my brake boost vaccum pump impeller is destroyed.

devinsixtyseven

I would suspect the fuel trim codes are related to the failed EGT sensor, since the ECU fails to rich to protect the engine if the EGT reading seems implausible. The O2 sensor may just be dead like the EGT...replace, reset, check, move on.

I have read several owners were able to fix their EGT sensors simply by re-soldering the connection inside each box, haven't done this yet on mine but meaning to as the EGT has become intermittent.

heavykrush2

Thanks. Will pull the EGT and let you know.

heavykrush2

Anyone know which EGT sensor is number 1? Drivers or passengers?

devinsixtyseven

Based on firing order.

Bank 1 is passenger side...fortunately that means "the easy one". Unfortunately, I've also read because the ECU is looking for a difference between the two readings, the sensors must be replaced in pairs, hence the "kit" part number replacing the old single sensor part numbers, so you still get to deal with the driver's side sensor.

heavykrush2

Ok gents, fixed the brake boost pump and the EGT sensors but still have #17965.

17965 - Charge Pressure Control: Positive Deviation
P1557 - 35-00 - -

From the Ross Wiki I should:

Check Hoses/Pipes to/between Components
Check Solenoid Valve for Boost Pressure Control (N75)
Check / Clean / Replace Charge Pressure Control Check / Clean mechanism for variable nozzles

I can do an output test on the N75 but how do I check it?

heavykrush2

Never mind... found this: Audi Workshop Manuals > A3 Mk1 > Power unit > Motronic fuel injection and ignitionsystem (4-cyl. turbo) > Mixture preparation system, electronic inj.,Gas > Checking the boost pressure system > Checking solenoid valve for boost pressure control