SEAT Workshop Service and Repair Manuals > Leon Mk2 > Power unit | SDI diesel injection and preheating system | Fuel preparation system Diesel injection | Components and functions: checking

Speedometer senderG21 checking

Speedometer sender -G21- checking

Special tools and workshop equipment required

t	Hand multimete -V.A.G 1526A- or multimeter -V.A.G 1715-

t	Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3B-

t	Auxiliary measuring set -V.A.G 1594A- or -V.A.G 1594C-

t	Test box -V.A.G 1598/18A-

t	Current flow diagram

Note!

To check the speed signal, the vehicle must be driven. To do this, a second person is necessary.

Caution

Secure fault reader to rear seat and operate from this position.

Test sequence

–	Connect fault reader -V.A.G 1551- (V.A.G 1552) and select engine electronics control unit with the “address code” 01. When doing so the engine must be idling. (Fault reader: Connecting and selecting the engine electronics control unit → Chapter.)

Indicated on display:

–	Press keys 0 and 8 for the function “Read measured value block” and confirm entry with Q-key.

Rapid data transfer                 HELP

Select function XX

Indicated on display:

–	Press keys 0, 0 and 6 for “Value group number 6” and confirm entry with Q-key.

–	Carry out a test drive and compare the display reading (a second person is required) with the speedometer reading.

Read measured value block           HELP

Enter value group number             XXX

Specification, display zone 1: approx. gearbox speed

–	Press the →-key.

–	Press keys 0 and 6 for the “End output” function and confirm entry with Q-key.

If no speed is displayed:

Read measured value block 6           ->

     55 km/h    255  0  0    000000    0

–	Connect test box -V.A.G 1598/18- to control unit wiring harness.

–	Bridge test box sockets 1 + 42 using auxiliary cables from -V.A.G 1594A- or -V.A.G 1594C-.

–	Set the multimeter to the voltage measurement range and connect it between test box sockets 43 + 33.

–	Switch ignition on.

–	Turn the front wheel, observing the displayed voltage. Specification: oscillating between 0 and 5 volts min.

Note!

If necessary, hold the front right wheel to prevent it from turning.

If the display does not fluctuate:

–	Check wiring to speedometer or speedometer sender: → Current flow diagrams, Electrical fault finding and Fitting locations.

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