VCDS will tell you exactly WHEN the failure is occurring. Without doing an output test and such, it's hard to diagnose. It may be failing but due to check valves, you're not noticing it. Hard to say.

VCDS is a worthwhile investment...

 

I guess I am leery about using scanners esp without training on interpreting output. I have a basic OBDII scanner and it is helpful for very basic codes and readings. But I have seen here and other forums people post the output and dont know how to interpret it. One thing I have seen is, a code that something has failed may not mean that component has failed, its really something somewhere upstream or downstream. I've never seen what the VCDS does, other than a few times at the shop.

I do know when this happens is when it shifts during a hard acceleration up a grade onto a freeway onramp or up a steep hill.

SO...if I had the VCDS on the car whilst driving, and I can get it to do the error, it will not only tell me what the pump is doing (or not) but also, vacuum conditions? It may not tell me which check valve is foo, but that its vacuum.

Maybe the vacuum problem is causing the pump to give this intermittent failure error?

 

I read in SSP-257 on the vacuum pump that it does run for 1-2 seconds on engine start-up. Thats what I have seen with my vacuum gage, as above.

I may try to diag these check valves. I have a vacuum pump.

This is what I found on the Ross Tech Wiki:

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17887/ P1479/005241 - Brake Boost Vacuum System: Mechanical Failure

Possible Causes
Fuse(s) faulty
if the blade wheel (rotor) in the vacuum pump is stuck, most probably a fuse will burn
Hoses from/to Brake Boost Vacuum Pump faulty
Brake Boost Vacuum Pump faulty
the blade wheel (rotor) in the vacuum pump is stuck
Possible Solutions
Check / replace fuses
check if the blade wheel (rotor) of the vacuum pump is stuck, otherwise the fuse will burn again
Check Hoses from/to Brake Boost Vacuum Pump
Check Brake Boost Vacuum Pump
check if blade wheel (rotor) is stuck
Perform Output Test
Perform Short Trip in Basic Settings. Group 008 is commonly the self test for this system and may be activated Key On, Engine Off. If needed activate basic settings using [On/Off/Next] and pump the brake pedal.

Special Notes
When this fault is stored in conjunction with misfire and system lean fault codes check the PCV system and any other possible sources of engine mechanical vacuum leaks. Although PCV failure is most common on the 1.8T engines equipped with the auxiliary vacuum pump, any engine with low vacuum can cause that electric pump to run excessively - resulting in this fault code.

-----------------------------------------------------
AFAIK the pump is running as intended. No braking problems. No noises. No blown fuses. Just this fault under this condition. Sounds like vacuum to me. Unless it is the pump but, it I dont expect it would give this code under these conditions. Am I wrong?

 

It will record the error, the time it occurred and what the error is. (voltage loss, low vac, whatever) It may or may not show the vac pressure.

It will lead you in the right direction. You'll still have to think to figure it all out. ;- )

 

I recently did a scan for trouble codes and one popped up. 005241, brake boost vacuum system
P1479-008 mechanical failure.

Any idea where I can locate the brake boost vacuum pump on the V8 FSI? I'd like to check hoses for a leak.
.

 

Perry01 this comes from my Bently manual

Sent from my iPhone using Tapatalk

 

Great, I'll take a look when there is daylight. Thanks!
.

 

Getting Brake Boost Vacum System Fault & Secondary Air Injection System Bank 2 Fault

Hello Team,

Getting the same/similar error. Mine came about after I swapped out both (left & right) my lower and upper control arms with new ones, as well as new front brake pads last weekend. When I got the car back I noticed I needed to brake harder inorder to stop the car normally and I was also hearing some air/blowing sounds on the front driver's side just above the air suspension and near that MAF. I initially thought the mechanics had messed up in putting back together the air shock when they changed out the upper control arm.

In any case I scanned it with VCDS and got the below 2 faults:-

Saturday,23,September,2017,09:16:43:20387

Address 01: Engine Labels: 079-907-560-BAR.clb
Control Module Part Number: 7L0 907 560 A HW: 7L0 907 560
Component and/or Version: 4.2l V8/4V 0030
Software Coding: 04210003590F0560
Work Shop Code: WSC 31414 790 00001
VCID: 2F6D7640BD52EF3940-5140
2 Faults Found:

005241 - Brake Boost Vacuum System
P1479 - 008 - Mechanical Failure - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 0
Fault Frequency: 8
Reset counter: 255
Mileage: 87051 km
Time Indication: 0
Date: 2017.09.18
Time: 17:20:51

Freeze Frame:
RPM: 2320 /min
Load: 82.7 %
Speed: 28.0 km/h
Temperature: 96.0°C
Temperature: 52.0°C
Absolute Pres.: 810.0 mbar
Voltage: 14.097 V

005137 - Secondary Air Injection System; Bank 2
P1411 - 002 - Insufficient Flow - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 0
Fault Frequency: 8
Reset counter: 255
Mileage: 87051 km
Time Indication: 0
Date: 2017.09.18
Time: 17:20:51


Readiness: 0000 0000