Really annoying Emissions light problem

[Low Fuel]

Hi guys,

Hope you can help, My A4 2.0 tdi 140 blb has the Check emmisons light on.

Took it to audi and scan came back as p0101 MAF "range performance"

So i ordered new Bosch MAF fitted it and all was well for 100 miles then it came back on, P0101 fault but this time "Implauasable signal"

Thought it may have been a spike so reset and came back on in 50 miles, Same implausable signal.

Cleaned out EGR and Throttle body that were really caked up but its back on after 20 miles, The car is smoking quite bad but mpg is still good and power is ok.

Any ideas guys as Audi want £105 PH and i havent got that as i used all my saving and then some to buy the car :/

Many thanks for looking.

 

[rowdyboy]

Which code reader are you using?

 

[Low Fuel]

My cousin has his own garage, It is a vag reader.

 

[rowdyboy]

I only ask because when I used my mates general code reader, I had the same message. When I used the full, proper VCDS, there was no such problem.

 

[Low Fuel]

Just an update of sorts:

Light is coming back on quicker and quicker now, It seems whatever problem it has is getting worse.

Also it drives fine for a while with no smoke whatsoever then the next minute its pouring out the back.

Im now thinking a sticking EGR valve or a boost leak, That make sense to you guys?

 

[hades-]

02 sensor
cat

 

[Low Fuel]

Hmm hadnt thought of that, Thanks mate.

Though wouldnt that be given me a fault ? all im getting on vag com is p0101 MAF fault, Implausible signal or Range performance.

 

[hades-]

check for leaks
6485/P0101/000257 - Mass Air Flow Sensor (G70): Implausible Signal [h=4]Possible Symptoms[/h]

• Loss of Power
• Erratic Idle

[h=4]Possible Causes[/h]

• Mass Air Flow Sensor (G70) faulty
• Air Leak(s) after Mass Air Flow Sensor (G70)
• Intake Air Filter dirty/faulty
• Ground Spots corroded or Paint Residue
• Wiring and/or Connections from/to Mass Air Flow Sensor (G70) faulty

[h=4]Possible Solutions[/h]

• Check Intake Air Filter
• Check Mass Air Flow Sensor (G70)
• Check Ground Spots
• Check Wiring and/or Connections from/to Mass Air Flow Sensor (G70)

[h=4]Special Notes[/h]

• In MY 1995-2002 (?) in Europe at VW-diesel-cars G70 had the bad reputation of slowly losing his performance, causing loss of power. It's not a matter of defective or breaking down, but it is filthy / dirty (not easy to clean). You can check functionality by making a log in [01-engine], [meas.blocks-08], group 003 (3e gear, full throttle, from 1700-4000rpm)