Checking ignition transformer and output stage — VW

ALL
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

Test box V.A.G 1598/18
Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
Adapter set V.A.G 1594
Diode test lamp V.A.G 1527
Current flow diagram

Check conditions

Hall sender in distributor must be OK.

Checking ignition transformer

Pull connector and H.T. cable off ignition transformer (N152).
Check primary resistance between terminals 1 and 15.
Specification: 0.5...1.5 ω
Check secondary resistance between terminals 4 and 15.
Specification: 2.5...4 kω

If the specifications are not attained:

Replace ignition transformer => Page
28-3
, item
4
.

Checking voltage supply

Pull 3-pin connector off ignition transformer -arrow-.

Connect multimeter to measure voltage using aux. cables from V.A.G 1594 to the contacts 1+3 of the disconnected connector.
Switch on ignition.
Specification: min. 11.5 V

If no voltage is present:

Switch off ignition.

Check wire between 3 pin connector contact 1 and earth for open circuit according to current flow diagram.
Wire resistance: Max. 1.5 ω

Check wire between 3 pin connector contact 3 and relay plate for open circuit according to current flow diagram.
Wire resistance: Max. 1.5 ω

Checking activation

Pull plug -arrows- off all injectors.

Connect diode test lamp V.A.G 1527 using aux. cables from V.A.G 1594 and adapters V.A.G 1594/15 to contacts 2+3 of the connector.
Operate starter and check ignition signal from engine control unit.
LED must flicker

The LED does not flicker:

Remove wiper arms and cowl panel:

=> Electrical system; Repair group 92; windscreen wiper system; removing and installing windscreen wiper system
Electrical system
windscreen wiper system
removing and installing windscreen wiper system

Connect test box V.A.G 1598/18 to control unit wiring loom.
Check wire between test box socket 24 and 3 pin connector contact 2 for open circuit according to current flow diagram.
Wire resistance: Max. 1.5 ω
Additionally check wires for short to one another.
Specification: ∞ω

If no wiring fault is detected and voltage was present between contacts 1+3:

Replace engine control unit
=> Page
24-99
.

If the voltage supply and activation is OK.:

Connect 3 pin connector and H.T. cable to ignition transformer.
Connect diode test lamp using aux. cables and clamps to the contacts 1 and 15 on ignition transformer.

Warning!
During the following test do not touch the terminals of the ignition transformer or test cables.
Operate starter.
The LED must flicker