1996 AUDI A8 checking

24-122

Checking signal to EVAP canister purge
regulator valve

If LED test light does not blink, or stays on:
If LED test light does not blink: - Connect VAG1527B LED voltage tester between connector terminals 1
(B+) and 2.
- Start output Diagnostic Test Mode (DTM) for EVAP canister purge
regulator valve -N80- page 01
-51
.
LED must blink
- Connect VAG1598/22 test box to ECM harness connector page 01
-
67
.

If LED test light stays on: - Check wiring between connector terminal 2 and Motronic ECM terminal
15 for open circuit or short circuit to B+.
- Check wiring between connector terminal 2 and Motronic ECM terminal
15 for short circuit to Ground.
Pa
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24-124

Leak Detection Pump (LDP), checking


Note:
Component locations page 24
-1

Electrical testing

If resistance is NOT OK: - Disconnect harness connector for LDP -V144-.
- Connect multimeter US1119 (Fluke 83 or equivalent) and check
resistance at leak detection pump. Specified values:

Connector terminal 1 to terminal 3: 640-720

Connector terminal 2 to terminal 3: 11.0-21.0
- Replace leak detection pump -V144-.
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24-125

Voltage supply, checking

If LED tester does not light: - Disconnect harness connector for LDP -V144-.
- Connect VAG1527B LED voltage tester between connector terminal 3
(B+) and engine Ground.
- Start engine and run engine at idle.
LED must light up.
- Check fuse for LDP -V144-.
- Check wiring for open circuit between terminal 3 and fuse, according to
wiring diagram.

Specified value: max. 0.5 .- Check fuel pump relay and signal to relay page 24
-95
.
Pa
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) and i
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24-126

Intake air system, checking for leaks


Required special tools and test equipment

VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable
Engine leak detector spray G 001 800 A1

Notes:
If there are leaks, intake manifold vacuum will
draw in the leak detector spray with outside air.
The spray reduces the ability of the fuel/air
mixture to ignite, which causes a drop in engine
speed and a significant increase in CO-content.
Observe the safety precautions listed on the
container.

Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) page 01
-8 .
Rapid data transfer
HELP
Select function XX

Indicated on display
Pa
ge 163 of 166 Motronic Multi
port Fuel In
jection
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) and i
gnition s
ystem
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yp
e=re
pair&id=AUDI.B5.FU03.24.1