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View Full Version : 2001-2005 A4 - Engine Check Light - Brake Boost - System too lean - System too Rich



A4nutter
08-09-2009, 02:49 PM
Can anyone help?

I have a 2001 A4 2.0 SE mutlitronic (petrol) (2001-2005 model)

My engine check light in on and throwing up the following faults:

1. Brake Boost System: Mechanical Failure. P1479

2. Please check DTC memory of instrument cluster: Open circuit P1654

3. Fuel trim: Bank 1 (add) System too lean P1136

(sometimes says system to rich)

I have had the car into two different garages a total of 5 times now. One replaced the air hoses. Both say they can’t find anything wrong and switch off the light, only for it to come back on in a day or so.

I am no mechanic but the car seams to be running and braking fine and I am not noticing any reduction in power or fuel economy.

Can anyone suggest anything when these faults are together?

Cheers

VAGMAN54
09-09-2009, 08:54 PM
did you check the instrument panel for codes ? fuel trim (add) is an idle problem with the fuelling,have you cleaned out the throttle body and reset the basic settings ? carnt help with your boost system failure its not one i have come across before

A4nutter
10-09-2009, 09:41 AM
Thanks for your response VAGMAN54,

Yes, I have check for codes, (P1479, P1654, P1136 etc) but their not much help on itentifying the actual problem.

I havent tried cleaning the trottle body (car has 63k miles on it) but will try that at the weekend. Dont know if that would effect the brake boost though?

Sam
10-09-2009, 09:56 AM
1.

http://wiki.ross-tech.com/index.php/17887/P1479/005241

P1479:

Possible Causes

* Hoses from/to Brake Boost Vacuum Pump faulty
* Brake Boost Vacuum Pump faulty

Possible Solutions

* Check Hoses from/to Brake Boost Vacuum Pump
* Check Brake Boost Vacuum Pump
o Perform Output Test
o Perform Short Trip

3.
http://wiki.ross-tech.com/index.php/17544/P1136/004406

P1136

Possible Solutions

* Check Mass Air Flow (MAF) Sensor
* Check Fuel Pressure Regulator
* Check Fuel Pump
* Check Intake/Exhaust System for Leaks
* Check Secondary Air Injection for Leaks
* Check Vacuum Lines for Leaks

As for number 2, have you scanned the instrument cluster for codes - you've scanned the car to get the above, but it would appear the 2nd code is asking you to scan the actual cluster.

k6rff
14-10-2009, 09:45 PM
Hi,
I'm no expert but had your fuel faults on a 2002 A4 1.8T. Was eventually guided by local vw specialist to a small hose - L shaped emerging from the mid inlet manifold and going backwards. With the engine running it appeared circular but was bifurcating into two parallel tubes a few cms along. It appeared pefect but I could not see the reason for it becoming two pipes. With the engine off it became one circular pipe - it was just a perished vacuum hose that was being sucked inwards! Happened at c50k

May not help but may solves yours or anothers problem.

Cost of hose £3.00 !!!!