SEAT Workshop Service and Repair Manuals > Leon Mk2 > Power unit | 3-cyl. diesel engine, mechanics | Fuel preparation system Diesel injection | Supplementary signals: testing | Data bus: testing | If the resistance value is outside the tolerance range:

If the resistance value is outside the tolerance range:

–	Free the terminal connector (arrow -1-) of the ABS control unit and remove it (arrow -2-).

Note!

The ABS control unit is located in the hydraulic unit, in the engine compartment.

–	Test the data bus CAN wiring for short circuits between wires:

–	To do so, re-measure the resistance between female contacts 6 + 7 of the test box Target value: ∞ Ω

If the target value is not reached (the wiring has a short circuit between wired):

–	Eliminate the wiring fault following the wiring diagram: → Current flow diagrams, Electrical fault finding and Fitting locations

If the target value is reached (the wiring has no short circuit between wires):

–	Attach test box -V.A.G. 1598/21- to the wiring harness of the ABS control unit.

–	Following the wiring diagram, test the data bus CAN wiring between the female contacts of test box -V.A.G. 1598/21- and -V.A.G. 1598/31- for open circuits:

-V.A.G. 1598/21-	-V.A.G. 1598/31-
female contact 10 female contact 11	female contact 6 female contact 7
Wiring resistance: 1.5 Ω max.

–	Also test the wiring for short circuits to positive, battery and earth.

If no fault is found in the wiring:

–	Replace the ABS control unit: → Brake systems; Rep. Gr.45

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