SEAT Workshop Service and Repair Manuals > Leon Mk2 > Power unit | 4 cyl. diesel engine with distributor pump | Fuel preparation system Diesel injection | Additional signals: checking | Speed signal: checking

Checking process

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.

–	Connect fault reader -V.A.G 1551- (-V.A.G 1552-). Start engine and select “Address code” 01 to select engine control unit.

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 “Display 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

Enter number group values XXX

Specification, display zone 1: approx. driven speed

If no speed is displayed:

–	Press → key.

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

–	Switch off ignition.

Read measured value block      6       →

     0 km/h     0 0 0     000000     255

–	Connect test box -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.

–	Connect multimeter to measure voltage between test box sockets 4/5+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 from contact 20 of engine control unit connector to dash insert panel for open circuit or short. → Current flow diagrams, Electrical fault finding and Fitting locations

SEAT Workshop Service and Repair Manuals