Jetta GL L4-1.9L DSL Turbo (ALH) (2001)
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Brake Signal: Testing and Inspection
With Manufacturer's Scan Tool
Brake Light Switch and Brake Pedal Switch Signal, Checking
The Diesel injection system operates with a throttle position sensor. For safety reasons, the engine is regulated when the brakes are operated. The ECM
requires signals from the brake light switch and also the brake pedal switch. This means that if the brakes are operated when the accelerator pedal is held
at a constant position the engine is immediately reduced to idling speed. Incorrectly adjusted switches may lead to unwanted regulating action.
Special tools and equipment
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VAG 1551/1552 Scan tool with adapter cable VAG 1551/3
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Test box VAG 1598/22
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Digital multimeter US1119 (Fluke 83 or equivalent)
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Adapter set VAG 1594
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Wiring diagram
Checking conditions
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Fuses 13 and 43 must be OK.
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The battery voltage must be at least 11.5 V.
Test sequence
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Connect VAG 1551/1552 (Connecting scan tool and selecting engine electronics control module. See: Testing and Inspection/Scan Tool Testing
and Procedures
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Run engine at idle speed and press buttons -0- and -1- to select "Engine electronics" address word 01.
Indicated on display
Rapid data transfer
HELP
Select function XX
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Press buttons -0- and -8- to select "Read measured value block" function 08 and confirm entry with -Q- button.
Indicated on display
Read measured value block
HELP
Input display group number XXX
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Press buttons -0-, -0- and -6- to select "Display group number 6" and confirm entry with -Q- button.
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Observe display in display field 2.
Read measured value block 6
->
0 km/h 0 0 0 000000 255
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Specification: x 0 0
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Center display = Brake pedal switch
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Right-hand display = Brake light switch
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Operate brake pedal slowly.
Read measured value block 6
->
0 km/h 0 1 1 000000 255
