Checking the TSZ-H ignition system switching unit (VW Transporter T3)

Test conditions: Ignition coil and DLS system are normal.

Disconnect the idle speed control system switching unit connectors and connect them together, see Figure 28-101.



Disconnect the TSZ-M ignition system switching unit connector.

Measure the voltage between contacts 4 and 2 of the connector using a voltmeter.



Turn on the ignition.
Specified value: approximately battery voltage (12 V), otherwise determine from the electrical diagram and eliminate the open circuit.

Turn off the ignition.

Connect the TSZ-H ignition system switching unit connector.

Disconnect the Hall sensor connector (distributor).



Connect the voltmeter to terminal 1 (-) and terminal 15 (+) of the ignition coil.



Turn on the ignition. The specified value is at least 12 volts. The voltage should drop to zero within 1-2 seconds. Otherwise, replace the TSZ-H unit and the ignition coil.

Touch the ground with the middle wire of the plug connection on the ignition distributor. The displayed value should briefly jump to about 2 volts. Otherwise, find and fix the break in the middle wire or replace the switching unit.



Turn off the ignition.

Connect a voltmeter to the outer contacts of the Hall sensor connector (distributor).

Turn on the ignition. Specified value: not less than 5 volts. Otherwise, determine and eliminate the open circuit between the Hall sensor connectors and the switching unit.

Connect the connectors to the DLS unit.

The original can be found at VWmanual