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View Full Version : Audi 1.8T Fuel Trim: Bank 1 (Mult): System too Lean



RedZed2009
12-07-2009, 04:24 PM
Hi All.

this fault has just come up today, any suggestions as to the likely fault? Many thanks in advance

Address 01: Engine
Controller: 06A 906 032 FC
Component: 1.8L R4/5VT 0001
Coding: 11500
Shop #: WSC 06435
WAUZZZ8Lxxxxxxx AUZ5Z0YNxxxxxxxxx
1 Fault Found:
17536 - Fuel Trim: Bank 1 (Mult): System too Lean
P1128 - 35-00 - -
Readiness: 0000 0000

kite
12-07-2009, 06:24 PM
Taken from the Ross-Tech Wiki

17536/P1128/004392 - Fuel Trim; Bank 1 (Mult): System too Lean
Possible Symptoms
Malfunction Indicator Light (MIL) active
Possible Causes
Mass Air Flow (MAF) Sensor faulty
Oxygen Sensor Control faulty
Oxygen Sensor(s) faulty
Fuel Injector(s) faulty
Possible Solutions
Check Mass Air Flow (MAF) Sensor
Check Oxygen Sensor Control
Check Oxygen Sensor(s)
Check Fuel Injector(s)

saabsalltheway!
12-07-2009, 06:29 PM
hi check this out
http://wiki.ross-tech.com/index.php/17536/P1128/004392

could also be a air leak on the inlet manifold, intake pipe after the air flow sensor any of the intercooler pipes and small vacuum pipes, also exhaust leak b4 the first lambda sensor
hth paul

RedZed2009
13-07-2009, 05:25 PM
Many thanks for the fast response guys. The car has only just come back from being serviced so I was not too happy about the engine light coming on. The exhaust bracket had also broken so this was welded up at the time. The A3 is my wife's car and we have had it from new (2001), it only has only covered about 36,000 miles.

Looking under the bonnet I have found the following pipe that was not reconnected after airfilter change in the service.... any ideas what this pipe feeds and could this have caused the fault? A long shot, but it would be nice if it was that simple.

Also, does anyone have a electronic copy of the service manual ?

http://i176.photobucket.com/albums/w165/maxz1000/nikon6002.jpg

a8 tech
13-07-2009, 06:58 PM
secondary air pipe for reducing emissions at low engine temperature by inducing air into the intake via a electric pump.This will affect lambda readings and as your vehicle uses the broadband type it may take some time to confirm if the fault code is erased as this fault code is based on fuel trim readings which are calculated by the lambda probe compensating air to fuel ratio and once the parameters are exceeded the ecu will illuminate the mil light and a fault code will store.In short refit the pipe and clear the fault code if the fault reoccurs post measured value blocks 32 and don't clear the code as you will lose important information for short term and long term fuel trim

RedZed2009
13-07-2009, 07:56 PM
many thanks.. I reconnected the pipe, then reset the fault code and went for a 30 mile drive. When I first drove off the car was hesitant to pick up but after 0.5 miles it went smooth again. I took the down the motorway at various speed also 100mph for a while and all seems fine again. Then back on the slower roads and car seem fine.

If the code comes up again I will post mearured blocks 32 as you suggest. I will have to figure out how to do this :)

A big thank you to all for the help so far. A great site.

RedZed2009
09-08-2009, 04:48 AM
The problem was the Mass Air Flow sensor.... car is running perfectly again. Many thanks for the assistance

orienteer
12-08-2009, 11:08 PM
The problem was the Mass Air Flow sensor.... car is running perfectly again. Many thanks for the assistance

My 2.0 bug has the same code unless I take it easy on the throttle while toddling about.

How did you confirm the MAF ?

I'll gladly change mine as it's about £40+ cheaper than a pre cat sensor change :1zhelp:

Regards, Ian

RedZed2009
30-06-2010, 05:35 PM
I took it to a service centre, who confirmed the MAF.

Bit of a waste on the diagnostics, but at least it confirmed the issue.

gpaul
02-07-2010, 05:45 PM
I took it to a service centre, who confirmed the MAF.

Bit of a waste on the diagnostics, but at least it confirmed the issue.

disconect your maf then drive it for a while if it run the same possible maf fault

RedZed2009
03-07-2010, 02:50 PM
disconect your maf then drive it for a while if it run the same possible maf fault

That sound a logical test... will remember that one for the future, thanks