SEAT Workshop Service and Repair Manuals

Ignition transformer -N152- checking

Special tools and workshop equipment required

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

t	Diode test lamp -V.A.G 1527 B-

t	auxiliary measuring set -V.A.G 1594 A- or -V.A.G 1594 C-

t	Test box -V.A.G 1598/22-

t	Current flow diagram

Checking conditions l  Fuses in perfect condition l  Battery voltage at least 11.5 V l  All electrical consumers, e.g. lights and rear window heating must be switched off. l  If the vehicle is equipped with an air conditioner/heating system, this must be switched off. l  Hall sender OK; checking → Chapter. l  Engine speed sender OK, checking → Chapter. Test sequence

–  Pull 4-pin connector off ignition transformer -arrow-. Voltage supply: checking

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

Connector, contact	Connector, contact
2	4
Switch ignition on
Specification: 11.5 V min.

–  Switch ignition off. If no voltage is present:

–  Check the cable for short circuit between:

Connector, contact	Relay plate
2	fuse 42
4	earth
Specification: 1.5 Ω max.

Activating checking   WARNING During the next test, the ignition transformer connecting parts or the test cables should not be touched.

–  Remove fuse 25.   Note Removing fuse No. 25 interrupts the voltage supply to the injectors.

–  Connect diode test lamp -V.A.G 1527 B- with adapter cables from -V.A.G 1594 C-, between:

Connector, contact	Connector, contact
1 (ignition output 1)	4
3 (ignition output 2)	4

–  Operate starter and check the ignition signal from engine control unit. The LED must flicker. –  Switch ignition off. If the LED flickers and there is voltage between contacts 2 + 4: –  Renew ignition transformer -N152- → Item. If the LED does not flicker. –  Check wiring → . Cables checking

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

–  Check wiring for open circuit between test box and connector using current flow diagram.

Connector, contact	Test box -V.A.G 1598/22-, socket
1	57
3	71
Specification: 1.5 Ω max.

–  Additionally check wires for short to one another..    Specification: ∞ Ω If no wiring fault is detected and voltage was present between contacts 2+4: –  Renew engine control unit → Item. Secondary resistance checking

–  Check the secondary winding on terminal 4 between:

Cyl. (see illustration)	Cyl. (see illustration)
1	4
2	3
Specification: 4.0 … 6.0 kΩ (at 20 °C)

If the specifications are not attained: –  Renew ignition transformer -N152- → Item.