Skoda Workshop Service and Repair Manuals > Fabia Mk1 > Engine | 2.0/85 Engine, Fuel Injection | Mixture preparation system, electronic inj.,Gas | Engine control unit | Testing voltage supply for engine control unit

Testing voltage supply for engine control unit

Special tools and workshop equipment required

t	Vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3, 3A, 3B oder 3C-

t	Test box -V.A.G 1598/31-

t	Handheld multimeter, e.g. -V.A.G 1526 A-

t	Measuring tool set e.g. -V.A.G 1594 A, B oder C-

t	Current flow diagram

Test conditions

l	Battery voltage at least 11.5 V.

l	Fuses no. 3, 14, 17, 48, 52 and 56 must be in proper order.

l	Generator o.k., test → Current flow diagrams, Electrical fault finding and Fitting locations.

Test sequence

–	Connect vehicle system tester -V.A.G 1552-. Start engine and select address word 01 “Engine electronics” → Chapter.

–	Select function 08 “Read measured value block” and display group 004.

–	Read off readout in display field 2.

Specified value: min. 11,5 V

–	Select function 06 “End output” and switch ignition off.

If the specified value is not reached:

–	Connect test box -V.A.G 1598/31- to connector of wiring loom → Chapter. The engine control unit is not connected here.

Testing voltage of terminal 30

–	Measure supply voltage between sockets 1 + 62 of the test box:

Specified value: min. 11,5 V

If the specified value is not reached:

–	Test cable connections to relay plate according to the current flow diagram → Current flow diagrams, Electrical fault finding and Fitting locations.

Testing voltage of terminal 15

–	Use multimeter to measure voltage between sockets 1 + 121 at the test box.

–	Switch on ignition.

Specified value: min. 11.5 V

If the specified value is not reached:

–	Test cable connections to relay plate according to current flow diagram:

Reading measured value block         4   ->

 840 rpm     13.6V       95.0°C      62.0°C

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