1995 AUDI A8 check engine

24-39

- Repair open circuit if necessary.
If LED lights up:

Checking activation

Test requirement:

Internal resistance of valve OK

Note:
Voltage testers do not go out completely during low current pick-up
between activations by the ECM, but rather continue to glow a little and
then get slightly brighter during activation. - Slide back rubber grommet of fuel injector connector (arrow), but leave
connector connected.
- Connect VAG1527B voltage tester between sockets 2 (signal) and 1
(B+).
- Operate starter briefly (engine can also start).

LED must blink.
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24-40
If LED does not blink:

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

If wire connection is OK: - Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Cylinder
Fuel injector harness connector
Terminal
VAG1598/31 test box
Socket
1 2 96
2 2 112
3 2 88
4 2 97
5 2 113
6 2 89
- Repair open circuit or short circuit if necessary.
- Replace Engine Control Module (ECM) Page 24
-21
.
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24-41


Fuel rail with fuel injectors, disassembling
and assembling

1 -
Fuel distributor
2 -
to T-piece
3 -
Retaining clip
Check for secure fitting
4 -
O-ring Removing and installing Page 24
-43
Always replaceCoat with clean engine oil
5 -
Fuel pressure regulator
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24-44

- Disengage retaining clip and remove fuel
injector.

Note:
Fuel lines must be disconnected before replacing
fuel distributor.
Installation is reverse of removal, noting the
following:

Remove O-rings at all opened connections.
(Never remove plastic cap from valve head
to replace front O-ring - pry O-ring off over
plastic cap).
Lightly lubricate O-rings with clean engine
oil.
Make sure fuel injectors are in place and
seated correctly
Check clip for unobstructed fitting.
Place fuel rail with secured fuel injectors
onto intake manifold, and apply uniform
pressure to press it in.

Tightening torque
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24-47

Checking Proper Seal

- Check proper seal of fuel injectors (visual
inspection). With Fuel Pump (FP) running, only 1
to 2 drops per minute may drip out per injector.

- If fuel loss is greater, stop Fuel Pump (FP) from
running (disconnect cable bridge) and replace
faulty fuel injector Page 24
-43
.

Checking Injection Quantity

- Insert fuel injector to be tested in a measuring glass from VAG1602
injection quantity test device.

- Connect one terminal of fuel injector to engine Ground (GND) using an
adapter cable and an alligator clip from VAG1594A connector test kit.
- Connect the second terminal of fuel injector to B+ using VAG1348/3A
remote control, VAG1348/3-2 adapter cable and assisting cable.
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24-51

Function test of Fuel Pump (FP) relay

- Remove driver-side storage compartment.

Repair Manual, Body
-Interior, Repair Group
68; Instrument Panel; Removing Driver
-Side
Storage Compartment


- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .

Ignition must remain switched on for this.

- Initiate output Diagnostic Test Mode Page 01
-
56
and activate Evaporative Emission (EVAP)
canister purge regulator valve -N80-.

A - If relay does not trigger:
Fuel Pump (FP) relay (at position 4 of central electrics in driver's
footwell, left) must trigger and Fuel Pump (FP) must run.
- Check voltage supply of Fuel Pump (FP) relay Page 24
-52
.
- Checking activation of Fuel Pump (FP) relay Page 24
-52
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24-53


If relay triggers now, but didn't during output DTM:
If relay does not trigger:
Fuel Pump (FP) relay (at position 4 of central electrics in driver's
footwell, left) must trigger.
- Replace Engine Control Module (ECM) Page 24
-21
.
- Remove cable bridge.
- Remove Fuel Pump (FP) relay.

If specified value is not obtained:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect multimeter to terminal 19 of relay socket and Ground (GND)
for voltage measurement.

Specification: approx. battery voltage
- Check wire connections.
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24-54
If specified value is obtained:

If no malfunctions are detected:
Check voltage supply for Fuel Pump (FP) and components - Check the following wire connection for open circuit and short circuit to
Ground (GND) and B+:
Central electric
in driver-side footwell, left, position 4
Terminal
VAG1598/31 test box


Socket
16 65
- Repair open circuit or short circuit if necessary.
- Replace Fuel Pump (FP) relay -J17-.
- Re-connect Engine Control Module (ECM).

- Remove fuses S228, S229, and S234 (positions 28, 29, and S234)
from fuse holder.
- Initiate output Diagnostic Test Mode Page 01
-56
and activate
Evaporative Emission (EVAP) canister purge regulator valve -N80-.
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