AUDI A4 2000 B5 / 1.G APB Engine Evaporative Emission Syst

24-134


Evaporative Emission (EVAP)
system, checking

Evaporative Emission (EVAP) Canister
Purge Regulator Valve -N80, checking


Checking for leaks
If there is no electrical signal (not activated) the
solenoid valve remains closed.

- Disconnect hoses from Evaporative Emission
(EVAP) Canister Purge Regulator Valve -N80.

- Start output Diagnostic Test Mode and select
Evaporative Emission (EVAP) Canister Purge
Regulator Valve -N80 Page 01
-75
.
Output Diagnostic Test Mode EVAP canister pur
ge re
gulator valve -N80

Indicated on display
The valve should click and should open and close (test by blowing into
auxiliary hose).
- If valve does not click, carry out electrical test of Evaporative Emission
(EVAP) Canister Purge Regulator Valve Page 24
-135
.
- If valve does not open and close properly, replace Evaporative
Emission (EVAP) Canister Purge Regulator Valve.
Pa
ge 1 of 6 Eva
porative Emission
(EVAP
) system, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.3

24-135

Electrical testing of Evaporative Emission
(EVAP) Canister Purge Regulator Valve -N80

- Disconnect connector from Evaporative
Emission (EVAP) Canister Purge Regulator
Valve-N80.

If the specification is not obtained:
If the specification is obtained: - Measure resistance between contacts on valve using hand-held
multimeter Fluke 83 (or equivalent).
Specified value: 22 - 30 ohm
- Replace Evaporative Emission (EVAP) Canister Purge Regulator Valve
-N80.
- Check voltage supply Page 24
-136
.
Pa
ge 2 of 6 Eva
porative Emission
(EVAP
) system, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.3

24-136

Checking voltage supply to Evaporative
Emission (EVAP) Canister Purge Regulator
Valve (solenoid valve)

Note:
The Evaporative Emission (EVAP) Canister
Purge Regulator Valve receives its power supply
via the fuel pump relay.

Test requirements

Fuse for EVAP valve OK

- Disconnect harness connector on Evaporative
Emission (EVAP) Canister Purge Regulator
Valve -N80.

The diode test lamp should light up.
If diode test lamp does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations - Connect VAG1527 diode test lamp between engine Ground (GND) and
socket 1 on connector.
- Operate starter.
- Check continuity of wiring from socket 1 to fuel pump relay via fuse.
Repair open circuit if necessary.
Pa
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porative Emission
(EVAP
) system, checkin
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11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.3

If the diode test lamp lights up, check activation Page 24
-137
. - If wiring is OK, check fuel pump relay Page 24
-54
.
Pa
ge 4 of 6 Eva
porative Emission
(EVAP
) system, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.3

24-137

Testing activation of Evaporative Emission
(EVAP) Canister Purge Regulator Valve

The diode test lamp should blink.
If the diode test lamp does not blink or lights up continuously: - Connect VAG1527 between diode test lamp sockets 1 (B+) and 2 of
harness connector.
- Start output Diagnostic Test Mode (DTM) and select Evaporative
Emission (EVAP) Canister Purge Regulator Valves -N80 Page 01
-
75
. (To initiate DTM a second time, the engine must be started and
switched off)

- Connect VAG1598/31 test box to multi-pin harness connector for
engine control module. Do not connect to the engine control module
itself Page 24
-20
.
Pa
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porative Emission
(EVAP
) system, checkin
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11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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e=re
pair&id=AUDI.B5.FU04.24.3

24-138
If the diode test lamp lights up continuously:

If the diode test lamp does not flash:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If no short circuit or open circuit is found - Check for short circuit to Ground (GND) in wiring between contact 2 on
EVAP valve harness connector and socket 64 on test box.
- Check for open circuit as well as short circuit to B+ in wiring between
contact 2 on EVAP valve harness connector and socket 64 on test box.
Resistance in wiring: max. 1.5 ohm- If necessary, repair short circuit to Ground (GND) or open circuit.
- Replace Motronic Engine Control Module (ECM) -J220 Page 24
-24
.
Pa
ge 6 of 6 Eva
porative Emission
(EVAP
) system, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.3