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Performance issue after EGR blanking


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2006 Audi A4 B7 2.0TDI

I wonder if anyone can help?

Yesterday, I had the EGR valve blanked off using two blanking plates.

The chap that did the work is a mate that works for Audi. Admittedly, he had not performed this mod before but obviously knows where everything is, etc. Anyway, he blanked off the EGR valve and I gave the inlet manifold a thorough clean.

Once the work was done, I drove off for a test drive. The engine warning light appears on the dash but I was half-expecting that, from having read all of the various threads about EGR blanking/delting.

The real concern for me is that the car’s performance has taken a turn for the worse. The turbo doesn’t kick in for a lot of the time when accelerating. It comes on now and again but it is intermittent. I’m not sure but I think the car may be going in and out of ‘limp home’ mode.

I spoke with my mate about the problem and we think the light on the dash and the performance issue are related. He thinks it may have something to do with the MAF sensor but we aren’t sure.

I’ve read on the threads about EGR blanking that you should also remove and block a hose vac that connects from the EGR valve to a solenoid. However, on my car I couldn’t locate such a vac hose. The only vac hose I could find was connected to the turbo actuator front left of the engine cover. However, blocking this made no difference.

I am loathe to pay a tuning company money for diagnosing the problem and cancelling the dash light if some kind soul out there could perhaps advise further, preferably someone with an A4 B7 TDI.

Many thanks,


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  • 2 weeks later...

Hi everyone,

I have an update....

I asked Superchips if they could write in an EGR delete into my remap. They charged me £50 plus VAT and promptly sent me the new map. I used my Bluefin device to d/load the new map to my car.

The engine warning light disappeared but the car was still going in and out of Limp Home Mode (LHM). Next day, I started the car up and the light was back on the dash :mad:

I emailed Superchips, who are very helpful, to be fair. They mailed me back saying that the fault code would need to be cleared and the EGR delete in the mapping would prevent the light from reoccuring.

Anyway, I located someone locally with VAG com. This chap scanned for fault codes and there was just the one showing:

1 Fault Found:

001027 - EGR Valve (N18): Malfunction

P0403 - 000 - - - Intermittent

Freeze Frame:

Fault Status: 00100000

Fault Priority: 0

Fault Frequency: 4

Mileage: 88859 km

Time Indication: 0

Freeze Frame:

RPM: 798 /min

Speed: 1.0 km/h

Duty Cycle: 84.4 %

Voltage: 13.76 V

Mass Air / Rev.: 480.0 mg/str

Duty Cycle: 41.4 %

Bin. Bits: 00000000

The fault code was promptly cleared and fingers crossed!

I got back into my car, started it up and drove off. Right

away, I could tell that the car was in LHM even though the

light had gone. We tried to clear further EGR fault codes

but it looks like they keep coming back :confused:

I don't understand, as once the fault code is cleared, the

ECU should now not be able to 'see' the EGR valve because it

has been deleted out in the remap.


I've already asked my mate to remove the blanking plates this

weekend and I just don't think you can do this on the B7/later


However, I would love for someone to let me know if they have

had any success with blanking the EGR on the later 2.0TDI.



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  • 2 weeks later...

Done right you will only get emmission workshop error on the dash, this is caused by the ecu seeing too much air drawn by the maf because the egr is not re-using the exhaust gasses to recirc the air to lower the maf reading. If this maf reading is too high and the ecu cannot bring the reading down the ecu will flag a dct as part of the EOBD2 EU emmsions law.

In the map you can only map out the requested air drawn from the ecu, which can be seen in blocks 3 using vagcom, the amount of air drawn from the maf should be set the the max value with will make the emmisions workshop light stay off. This is what Superchips would have done with your map file.

I think the problem you have is a closed loop rediness fault, ie the ecu not seeing any resistance from the N18 valve which flags the dct and limps the car due to it being linked to the emmssions (EU bullcrap), which as far as I know cannot be mapped out in the ecu mappinf. Your options are put the N18 back in place and cable tie it to the bulk head or find out what resistance the N18 pulls and pop to maplins and get a resistor and loop the connections on the plug with help of autodata.


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  • 12 years later...

I seem to have the same problem ,I bought the like it is with the EGR VALVE APPARENTLY BLOCKED OFF.The car has no ecceleration to speak of but is meant to be 160 plus break .would unblanking the EGR valve restore the performance?

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