2000 A3 1.8T Quattro - Fault Codes

[VaulterTim]

Hi guys,

Have posted this in the A3 Forum too but I think it is more specific to this one since VAG-COM is involved.

A friend has a few problems with the above car.

I took a quick look for him and retrieved VAG-COM fault codes as follows...

16621 - Manifold Pressure/Boost Sensor: Signal too low
16490 - Manifold Abs.Pressure or Bar.Pressure Range/Performance
16497 - Intake Air Temp.Circ High Input

I haven't had time to take a proper look yet but just wanted to know if anyone has encountered these before..?

With the engine running... when I reset the 16621 fault, the engine cuts out if only idling and dips when at constant off-idle engine speed. The other two, I am guessing, only appear when the engine is not running because it is not running. I'm assuming the engine needs to be running to avoid them because once reset they do not return unless I run the scan with the engine turned off.

I know there are a few obvious things to check and I will give it a good going over once he returns from holiday next week but a head start would be much appreciated if anyone has experience with this fault

Cheers

Tim

 

[Tallpaul]

The fault codes are only indications of the fault, they do not have any input back to there respective sources. I'm baffled that clearing that code causes the engine to stall!

All three appear related, but sould only be generated while the engine is running as they are all sensors relating to air intake/boost.

If you have full VAG-COM, log g/s; Boost requested vs Actual and N75 Duty Cycle.

In no particular order i'd check:

Leaking air hose
MAF
N75
DV

 

[VaulterTim]

Cheers dude,

Yes I had planned on checking all the above when I actually get the car here to look at it... I'm sure there will be something obvious... or at least I hope there will be!

Cheers

T

 

[VaulterTim]

Ok, sorted it... an hour from start to finish including VAG-COM check.

Traced fault to MAP sensor on top of intercooler. Bit awkward to get at which meant removing PAS reservoir, windscreen washer bottle and carbon canister, although that's not exactly rocket science! Once all are out of the way (about 20mins work) it was a simple matter of unplugging and unscrewing the sensor. Once it was out I noticed a completely bent back pin inside the sensor itself which clearly was not even entering the plug when it was pushed in place over the sensor itself. Someone has obviously been in there before and made a bodge of putting it all back together. Some careful prising of the pin, ensuring not to snap it, and then popping the plug back in place was all that was required.

It's done now and performing exactly how it should do... job done. Cleaned the MAF whilst I was at it along with IAT sensor, both were a bit gunked up and clearly hadn't been done in... well, maybe never!

Cheers

T