Checking voltage supply to diesel direct injection system - vehicles up to 06.94 — AUDI

ABP AEL
Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1594 A
V.A.G 1598 with V.A.G 1598/5

Checking voltage supply to excess voltage protection relay -J249

Test requirement:

Battery voltage at least 12.7 V

Switch on ignition.
Excess voltage protection relay -J249 at socket 1 on auxiliary relay carrier III, in passenger side footwell, must pick up (click)

Note:

Clicking of relay is not easy to hear and can best be established by way of touch.

Switch off ignition.

If relay does not pick up:

Remove bottom right A-pillar trim and right sill panel trim in area of front door.

=> General Body Repairs; Repair Group 70; Trims and covers;
General Body Repairs
Trims and covers

Remove relay from socket 1 of auxiliary relay carrier III in passenger side footwell.

Connect up multimeter for voltage measurement as follows.

Auxiliary relay carrier III in passenger side footwell, socket 1 / Contact · Measure to /
8 · Engine earth
2 · Battery positive

Specification: approx. battery voltage

Connect up multimeter for voltage measurement as follows.

Auxiliary relay carrier III in passenger side footwell, socket 1 / Contact · Measure to /
6 · Engine earth

Switch on ignition.
Specification: approx. battery voltage

Switch off ignition.

If reading does not match specification:

Use current flow diagram to eliminate open circuit in wiring.

If no fault is found:

Replace excess voltage protection relay -J249.

Checking voltage supply/terminal 15 of diesel direct injection system control unit -J248 and excess voltage protection relay -J249

Excess voltage protection relay -J249 OK

Reinsert relay.

With ignition switched off, use adapter V.A.G 1598/5 to connect test box V.A.G 1598A to engine control unit connector only (not to control unit) => Page
23-45
.
Connect up multimeter for voltage measurement as follows.

Vehicles up to 07.92:

Test box V.A.G 1598 A / Socket · Measure to
15 · Engine earth
16 · Engine earth
17 · Engine earth

Vehicles as from 08.92:

Test box V.A.G 1598 A / Socket · Measure to
16 · Engine earth
17 · Engine earth

All:

Switch on ignition.
Specification: approx. battery voltage in each case

Switch off ignition.
Connect up multimeter for voltage measurement as follows.

Test box V.A.G 1598 A / Socket · Measure to
18 · Battery positive
19 · Battery positive

Specification: approx. battery voltage in each case

If a reading does not match specification:

Use current flow diagram to eliminate open circuit in wiring/short circuit.