1999 AUDI A4 Ignition

20-156

Checking output wiring (vehicles with
electronic throttle control)

- Connect voltage tester VAG1527B as follows:Electrical connector terminal
Specification
2 Battery Positive
- Initiate Diagnostic Test Mode (DTM) Page 20
-146
.
-
Press button until following display is shown:
Output Diagnostic Test Mode LDP leak test

Indicated on display:
If LED does not blink:
LED must blink
- Switch ignition off.
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20-157


- Remove weatherstrip at plenum chamber -arrows-.
- Remove cover for plenum chamber -1- toward front.
- Remove cover for E-box in plenum chamber.

Note:
Disconnect or connect the Engine Control Module (ECM) connector only
with ignition switched off. - Carefully lever off clamp -arrow- with screwdriver.
- Unlatch clip and disconnect connector for Engine Control Module
(ECM).
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20-159
If you did not find any malfunction, however the
Leak Detection Pump (LDP) did not function
during the Output Diagnostic Test Mode (DTM):

- Replace LDP Page 20
-162
If the LED does not blink, although wiring is OK:

- Replace the Engine Control Module (ECM)

Repair Manual, Fuel Injection & Ignition,
Repair Group 24
- Generate readiness code:

Repair Manual, Fuel Injection & Ignition,
Repair Group 24
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20-160

Checking input wiring (vehicles with
mechanical throttle activator)

- Switch ignition off.

- Connect test box VAG1598/22 to harness connector Page 20
-153
,
"Checking output wiring."

Repair Manual, Fuel Injection & Ignition, Repair Group 24 - Check the following wire connections for open circuit or short circuit to
Ground or plus (B+): Electrical connector terminal
Test box VAG1598/22 socket
2 37
- Repair open or short circuit as necessary.
- Generate readiness code:
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20-161

Checking input wiring (vehicles with
electronic throttle control)

- Switch ignition off.

- Connect test box VAG1598/31 to harness connector Page 20
-156
,
"Check output wiring."

Repair Manual, Fuel Injection & Ignition, Repair Group 24 - Check the following wire connections for open circuit or short circuit to
Ground or plus (B+): Electrical connector terminal
Test box VAG1598/31 socket
1 80
- Repair open or short circuit as necessary.
- Generate readiness code:
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20-162

Leak Detection Pump (LDP) -V144,
removing and installing

Checking LDP Page 20
-139


Removing

- Remove left rear wheel.

- Remove left rear wheel housing liner.

Repair Manual, Body Exterior, Repair Group
66


- Cut tie wrap -1- and remove hose -2- .
- Disconnect hose coupling -3- after pressing tab.
- Remove nuts -arrows-.
- Switch off ignition.
- Remove LDP, unclip and disconnect connector.
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20-176


EVAP system leak detection circuit,
schematic diagram (vehicles with 1.8 ltr.
turbo engine)

Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Fuel
Injection & Ignition, Repair Group 24 1 -
Check valve
Location (light/dark side): as shown in
illustration
2 -
EVAP canister purge regulator valve -N80-Location: in engine compartmentChecking
3 -
Bleed line
From EVAP canister purge regulator valve
-N80-
LocationRight side under floor panFront-wheel drive: on floor pan in area of
fuel tank All-wheel drive: on fuel tank in area of fuel
tank
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20-180


EVAP system leak detection circuit,
schematic diagram (vehicles with 2.8 ltr.
engine)

Repair Manual, 2.8 Liter V6 5V Fuel Injection &
Ignition, Repair Group 24 1 -
Throttle actuator control module -J338-
2 -
EVAP canister purge regulator valve -N80-Location: in engine compartmentChecking:
3 -
Bleed line
From EVAP canister to EVAP canister
purge regulator valve -N80-
LocationOn right side under floor panVehicles with front-wheel drive: mounted
on floor pan in area of fuel tank Vehicles with all-wheel drive: mounted on
fuel tank
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11/18/2002 htt
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pair&id=AUDI.B5.GE04.20.5