Testing voltage supply for diesel direct injection system — AUDI

ATD AXR
Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1594 A
V.A.G 1598/31

With the ignition switched on, the injection system receives its voltage supply via diesel direct injection system relay -J322.

In order for relay -J322 to close, a voltage must be applied to the diesel direct injection system control unit via terminal 15. This means that relay -J322 is only earthed (via the diesel direct injection system control unit) if a voltage is applied to the control unit via terminal 15.

Note:

Fitting location for diesel direct injection relay -J322: in 13-slot relay carrier at left under dash panel, plug-in position 12.

Test requirement:

Battery voltage not less than 12.7 V
Fuses for engine electronics OK.

=> Current flow diagrams, Electrical fault finding and Fitting locations binder

Test sequence

Connect test box V.A.G 1598/31 to wiring harness for engine control unit.Do notconnect to the engine control unit itself.
Connecting test box to engine control unit without protective housing=>Page 23-49.
Connecting test box to engine control unit with protective housing=>Page 23-51.

Remove storage compartment on driver's side.

=> General body repairs, Interior; Repair group 68; Storage compartments, covers; Removing driver's storage compartment
General body repairs, Interior
Storage compartments, covers
Removing driver's storage compartment

Testing earth supply

Connect multimeter (voltage measurement range) as follows:

Test box V.A.G 1598/31 / Socket · Measure against
4 · Battery positive
5 · Battery positive

Specification: approx. battery voltage

If the specifications are not obtained:

Check wiring connections according to current flow diagram.

Checking voltage supply (terminal 15)

Connect multimeter (voltage measurement range) as follows:

Test box V.A.G 1598/31 / Socket · Measure against
37 · Engine earth

Switch on ignition.
Specification: approx. battery voltage

If the specification is not attained:

Test wiring for open circuits and rectify if necessary.

Testing voltage supply (terminal 30)

Connect sockets 4 and 18 of test box to each other using auxiliary cable from V.A.G 1594 A.

The relay -J322 (in 13-slot relay carrier at left under dash panel, plug-in position 12) should pick up audibly and perceptibly

If the relay does not pick up:

Check relay -J322 => Page 23-74.

If the relay picks up

Connect multimeter (voltage measurement range) as follows:

Test box V.A.G 1598/31 / Socket · Specification
1 + 5 · approx. battery voltage
2 + 5 · approx. battery voltage

Test the following wiring connections for open circuits:

13-slot relay carrier at left under dash panel, plug-in position 12 / Contact · Test box V.A.G 1598/31 / Socket
6 · 1
6 · 2

If no fault is detected in the wiring:

Testing diesel direct injection system relay -J322

Requirements for test:

Earth connection and voltage connection of engine control unit okay
Engine control unit connected.
Relay clicks when ignition is switched on.

Unplug relay -J322 in 13-slot relay carrier at left under dash panel, plug-in position 12.

Connect multimeter (voltage measurement range) as follows:

13-slot relay carrier at left under dash panel, plug-in position 12 / Contact · Measure against /
2 · Engine earth

Specification: approx. battery voltage

If the specification is not attained:

Test for open circuit and short to positive or earth in the following wiring connections:

13-slot relay carrier at left under dash panel, plug-in position 12 / Contact · Test box V.A.G 1598/31 / Socket
9 · 18

If no wiring fault is detected:

Replace engine control unit
Removing and installing engine control unit without protective housing=>Page 23-57.
Removing and installing engine control unit with protective housing=>Page 23-60.

If no wiring fault is detected and no voltage was present between contacts 1+2:

Renew relay -J322.