Checking UIS solenoid valves: Audi 1.9 TDI (AJM, AVF, AWX)

AVF AWX
Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1527 B
V.A.G 1594 A
V.A.G 1598/31
VAS 5051 with VAS 5051/1

Test sequence

Connect up vehicle diagnostic, testing and information system VAS 5051 => Page 01-2 and select vehicle system "01 - Engine electronics" from list. Engine must be idling.

Read measured value block, Display group 018, engine idling.

Display on VAS 5051:

Specification: "0" in all 4 display zones for properly functioning control

Terminate function "08 - Reading measured value block" by touching ◂ key.
Touch "06 - End of output".

If value other than 0 is displayed:

Checking actuation

Connect test box V.A.G 1598/31 to engine control unit wiring harness and also to engine control unit=>Page 23-50.

Connect up voltage tester V.A.G 1527 B as follows.
Briefly operate starter.

Test box V.A.G 1598/31 / Socket · Specification
114 + 116 · LED must flash
114 + 117 · LED must flash
114 + 118 · LED must flash
114 + 121 · LED must flash

If readings do not match specifications:

Check wiring => Page 23-38.

If readings match specifications:

Checking internal resistance

Connect test box V.A.G 1598/31 to engine control unit wiring harness. Actual engine control unit is not to be connected=>Page 23-50.

Connect up multimeter for resistance measurement as follows.

Test box V.A.G 1598/31 / Socket · Specification
114 + 116 · approx. 0.5 ω
114 + 117 · approx. 0.5 ω
114 + 118 · approx. 0.5 ω
114 + 121 · approx. 0.5 ω

Note:

Specification of approx. 0.5ωrelates to measurement directly at valve. With the measurement method employed, the wiring resistance is added to this so that the result obtained will always be 0.3 ... 0.5ωabove the specification.

If reading far exceeds specification or if result obtained is 0 ω or ∞ ω:

Remove cylinder head cover.

=> 4-cyl. TDI Engine, Mechanics; Repair Group 15; Removing and installing cylinder head; Removing and installing cylinder head cover
4-cyl. TDI Engine, Mechanics
Removing and installing cylinder head
Removing and installing cylinder head cover

Use screwdriver to prise connector off unit injector system -arrow-. To prevent tilting, press gently with finger against other side of connector.

With individual connectors unplugged, connect multimeter directly to valve for measuring internal resistance.
Specification: approx. 0.5 ω

If reading does not match specification:

Replace unit injector system.

If reading matches specification:

Checking wiring

Connect test box V.A.G 1598/31 to engine control unit wiring harness. Actual engine control unit is not to be connected=>Page 23-50.
Check for open circuit and short to earth/positive in the following wiring.

Cylinder · Valve connector / Contact · Test box V.A.G 1598/31 / Socket
1 · 2 · 116
2 · 2 · 117
3 · 2 · 118
4 · 2 · 121
All · 1 · 114

If necessary, eliminate open circuit in wiring/short circuit.

If no fault is found:

Replace engine control unit => Page 23-52.