SEAT Workshop Service and Repair Manuals > Leon Mk2 > Power unit | Manual 4-cyl. injection engine (4 valves), mechanics | Mixture preparation system, electronic inj.,Gas | Additional signals: checking | Speed signal checking

Test sequence

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.

Observe the valid safety precautions when carrying out a road test → Chapter.

–	Connect fault reader -V.A.G 1551- (-V.A.G 1552-). Start engine and use address code 01 to select engine control unit. (Connecting fault reader and selecting engine control unit → Vehicle diagnosis, testing and information system VAS 5051.)

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 4 for “Display group number 4” and confirm entry with Q key.

Read measured value block

Input display group number XXX

Indicated on display: (1...4 = Display fields)

–	Carry out test drive with a 2nd person to observe display.

–	Observe display in display field 3: Specification: approx. driven speed

–	Drive slower. The displayed value must decrease.

–	Press → key.

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

–	Switch off ignition.

If no speed is indicated or the display values reduce when driving slowly:

Read measured value block 4            →

–	Connect test box -V.A.G 1598/22- to control unit wiring harness.

–	Connect multimeter to measure voltage between test box sockets 2+20.

–	Switch on ignition.

–	Raise front left side of vehicle.

–	Rotate front wheel and observe voltage display. Specification: between 0 and at least 4 Volt fluctuating

Note!

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

If the display does not fluctuate:

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

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