Volkswagen Golf / Golf GTI / Jetta. Manual — part 102

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If no pressure drop is indicated:

- Proceed to "Checking Leak Detection Pump

V144- for internal leaks".

If pressure drop is indicated:

- Replace fuel cap and re-test.

- Proceed to "Checking Leak Detection Pump

V144- for internal leaks".

Checking Leak Detection Pump -V144- for
internal leaks

Basically, in the following procedure the EVAP
system will be filled with smoke, the engine
started and the LDP activated using the VAS
5051 or VAS 5052. With the LDP activated, and
after clearing initial smoke away from the LDP
area using compressed air, the system is then
filled with smoke again and rechecked for smoke
at the LDP filter.

Conditions

Ignition switched off

LDP is visible

Component Locations

Tester hose connected to fuel filler neck

VAS 5051 or VAS 5052 Diagnostic tool

connected to vehicle

Smoke generator connected to battery

- Turn KLI 9210 valve to "Test" and use smoke

generator trigger to fill system with smoke (wait
until smoke is coming out of the LDP filter).

Secondary air system

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- Start engine.

- From VAS 5051 Start-up screen, select "Vehicle

self diagnosis".

- Select vehicle system "01 - Engine electronics".

- Select Diagnosis Function "04 - Basic settings".

Secondary air system

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If LDP does not activate:

For some vehicles using Display
group 202 a similar screen appears
indicating "Test Off".

- Input appropriate display group

from table below on keypad.

Engine code

Display

group

AEB, AEG, AFP, AHA,

APH, ATQ, ATW, AUG,

AWD, AWM, AWP,

AWV, AWW, BDC,

BDF, BEV, BGD, BGJ

071

AVH, AZG, BAP, BBW,

BDP

202

- Press "Q" on keypad to confirm.

LDP should activate

If LDP does not activate:

If LDP activates:

- Select "Activating" button.

- Check electrical connections to

LDP.

- Check vacuum source to LDP.

Secondary air system

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A similar screen appears, Test is

"ON" (indicated by a "1" in position
5, -arrow-).

Position 1 -arrow- alternates

between "0" and "1" during pump
operation.

Secondary air system