SEAT Workshop Service and Repair Manuals > Leon Mk1 > Power unit | 4 cylinder injektion engine. (2.0l, 2 valve) | Mixture preparation system, electronic inj.,Gas

Voltage supply to the engine control unit: verification

Special tools and workshop equipment required

t	Hand multimeter -V.A.G 1526A- oder multimeter -V.A.G 1715-

t	Auxiliary measurement tool set -V.A.G 1594A- or -V.A.G 1594C-

t	Double connection engine testing unit -V.A.G 1598/31- (AZL engines) or -V.A.G 1598/22- (BBX engines)

t	Current flow diagrams

Test conditions

l	The fuses must be OK.

l	Battery voltage must be at least 11.5 V.

l	All consumer electrics should be connected, for example: the lights and the heated rear window.

l	Vehicles fitted with air conditioning must have it disconnected

l	Alternator OK.

Verification process

–	Connect test box -V.A.G 1598/31- to control unit wiring harness, without connecting the engine control unit (for BBX engines use the tester -V.A.G 1598/22-) → Chapter.

Note!

t	The voltage supply for the positive terminal of the engine control unit is made on the contact 3 (terminal 15) and on the contact 62 (terminal 30) for AZL engines and contact 5 (terminal 15) and contact 15 (terminal 30) for BBX engines.

t	The connection of the earth for the engine control unit is made on the contacts 1 and 2 for the AZL engines and contacts 2 and 28 for BBX engines.

–	Measure the voltage with the multimeter and the auxiliary cables of -V.A.G 1594 A- or -V.A.G 1594 C- as follows:

Test box -V.A.G 1598/31-, test box socket	Test box -V.A.G 1598/22-, female connector	Measure to
1	2	Battery positive
2	28	Battery positive
62	15	Engine ground
	Specification: about the battery voltage

Vehicles with engine identification letters AZL

–	Connect the engine control unit to the engine testing equipment -V.A.G 1594/31-.

–	Turn the ignition on.

Test box -V.A.G 1598/31-, female connector	Measure to
3	Engine ground
121 → Note	Engine ground

¹⁾	After disconnecting the ignition, the current supply relay for Motronic -J271- will still supply current to terminal 121 of the engine control unit for a maximum of 15 minutes. Specification: about the battery voltage.

–	Switch ignition off.

Continue for all vehicles

If the specifications are not attained:

–	Check wiring connections to relay plate according to current flow diagram: → Current flow diagrams, Electrical fault finding and Fitting locations.

–	Verification of the current supply relay for the Motronic -J271- → Chapter.

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