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Skoda Workshop Service and Repair Manuals

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Test brake light switch F and brake pedal switch F47 > < Testing signals from the air conditioning system

Fabia Mk1

Testing the speed signal
Testing the speed signal
Only for vehicles without ABS
The speed signal is generated by the speedometer sender -G22- and is produced in the dash panel insert. The produced signal enters at contact 20 of the engine control unit.
For vehicles with ABS/ ABS with TCS/ ABS with EDL and TCS/ESP → Chassis; Rep. Gr.45
Special tools and workshop equipment required
t  Vehicle system tester -V.A.G 1552 -
t  Diagnostic cable -V.A.G 1551/3- or -V.A.G 1551/3A- or -V.A.G 1551/3B-
t  Hand multimeter (e.g. -V.A.G 1526 A-)
t  Adapter cable set (e.g. -V.A.G 1594 A-)
t  Test box -V.A.G 1598/31-
Test condition
l  Operation and indication of speedometer o.k., → Electrical System; Rep. Gr. 90
Test sequence
  Note
t  The vehicle must be driven in order to test the speed signal. The assistance of a second person is required.
t  Comply with the safety instructions for a test drive.
–  Connect vehicle system tester - V.A.G 1552-. Start engine and select “address word” 01 Engine electronics.
–  Select function 08 “read measured value block” and display group number 006.
   
–  Readout on display:
–  Determine by means of a test drive whether the driving speed is displayed in display field 1.
  Caution
Secure the vehicle system tester to the rear seat and operate from that position.
–  If the driving speed is not displayed:
–  Select function 06 “End output” and confirm with Q.
–  Switch off ignition.
–  Connect test box -V.A.G 1598/31 - to the wiring loom on the engine control unit .
–  Connect the handheld multimeter to measure the voltage between bushes 4/5+20 of the test box -V.A.G 1598/31 -.
–  Switch on ignition.
–  Raise vehicle until the front left wheel is free.
–  Rotate front left wheel by hand and observe the voltage display on the handheld multimeter.
   Specified value: fluctuating between 0 and 4 V.
If the display does not fluctuate:
–  Check the following wire for interruption or short-circuit to earth or positive:
  
Reading measured value block         6   ->
0 km/h       000         0.0 %          255
Test box - V.A.G 1598/31-, bushDash panel insert contact
20 → Current flow diagrams and Fitting locations

–  If necessary eliminate wire interruption or short-circuit.
   

Test brake light switch F and brake pedal switch F47 > < Testing signals from the air conditioning system