Testing boost pressure - engine code AFN: Audi 1.9 TDI (1Z, AFF, AFN, AHU)

AHU AFN 1Z
Boost pressure is measured in the course of a test drive with the turbocharger tester V.A.G 1397/A and the fault reader V.A.G 1551.

Test prerequisites:

No leaks in intake and exhaust system
Compression, hydraulic tappets and injectors OK

Additionally connect measuring hose of turbocharger tester with T-piece to pressure conenction of intake manifold pressure sender and secure with hose clip.
Feed measuring hose over rear edge of bonnet and through right-hand window opening into passenger compartment.

Notes:

The hose connection must be absolutely tight to prevent measurement errors.
Make sure that measuring hose does not become trapped at the bonnet or side window.

Switch on turbocharger tester, set measuring range switch to -I- and attach measuring hose to connection -I-.

Warning!
Second person is required to operate V.A.G 1397/A and V.A.G1551.
Read measured value block 11
⇒
840 rpm
938 mbar
978 mbar
92 %
Read measured value block (function 08) and select display group 11, => Page .
Accelerate vehicle in 3rd gear from roughly 1500 rpm at full throttle.
At approx. 3000 rpm, simultaneously press memory button -M- on V.A.G 1397/A and PRINT button on V.A.G 1551.

Desired value on V.A.G 1397/A: 1.850...2.200 bar
Read measured value block 11
⇒
3090 rpm
1948 mbar
1989 mbar
62 %
Desired value on V.A.G 1551: 1850...2200 mbar (in display field 3)

Note:

The boost pressure level is to be determined with the turbocharger tester V.A.G 1397/A. The fault reader V.A.G 1551 is designed to check whether the boost pressure has also been recorded in the control unit.

If measured boost pressure is not OK:

Final control diagnosis
⇒
Solenoid valve for boost pressure limitation -N75
Perform final control diagnosis and actuate solenoid valve for boost pressure limitation => Page .

Solenoid valve must operate (can be felt by touching valve)...

If solenoid valve does not operate, test solenoid valve for boost pressure limitation -N75
=> Page
23-48

... and linkage of vacuum unit at turbocharger must move back and forth at least 3...4 times (as long as vacuum is present).
If linkage does not move, connect vacuum hand pump V.A.G 1390 to vacuum unit and test freedom of movement of linkage.
If linkage moves freely, test vacuum hoses => Page
23-55
.