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Polo Mk3

Power unit > Simos injection and ignition system > Ignition system, glow plug system > Servicing ignition system > Checking ignition transformer

Simos injection and ignition system
Servicing ignition system
Checking ignition transformer

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

  • ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
  • ◆ Diode test lamp V.A.G 1527
  • ◆ Adapter set V.A.G 1594
  • ◆ Test box V.A.G 1598/31
  • ◆ Current flow diagram

Check conditions

 
N24-0831
  • ● → Fuse No. 34 must be OK.
  • ● Battery voltage at least 11.5 V
  • ● All electrical consumers, e.g. lights and rear window heating must be switched off.
  • ● If the vehicle is equipped with an air conditioning system, this must be switched off.
  • ● Engine speed sender must be OK, checking .
  • ● The Hall sender must be OK,
    checking .
 
N28-0102

Test sequence

  • ‒ Remove cover over camshaft housing , Fig.1 .
  • ‒ → Pull 4 pin connector off ignition transformer (N152) -arrow-.

Checking voltage supply

 
N28-0133
  • ‒ → Using multimeter and adapter cables from V.A.G 1594 measure the supply voltage between contacts 2 (positive) + 4 (earth) of disconnected connector.
  • ‒ Switch on ignition.
         Specification: min. 11.5 V
  • ‒ Switch off ignition.

If no voltage is present:

 
A24-0094
  • ‒ → Check wire between 4 pin connector contact 2 and relay plate for open circuit according to current flow diagram.
         Wire resistance: max. 1.5 ω
  • ‒ Check wire between 4 pin connector contact 4 and earth for open circuit according to current flow diagram.
         Wire resistance: max. 1.5 ω
 
N24-0831

Checking activation

Warning!
During the following test do not touch the terminals of the ignition transformer or test cables.
  • ‒ → Pull fuel pump fuse No. 40 out of fuse holder.
 
A24-0094
  • ‒ → Connect diode test lamp V.A.G 1527 with adapter cables from V.A.G 1594 to
         contacts 1 + 4 (ignition output 1),
         contacts 3 + 4 (ignition output 2)
    of disconnected connector.
  • ‒ Get a 2nd person to operate starter and check the ignition signal from engine control unit.
         The LED must flicker
  • ‒ Switch off ignition.

If the LED flickers and there is voltage between contacts 2 + 4:

  • ‒ Replace ignition transformer (N152)
    => Page 28-4 , item 4 .

The LED does not flicker:

 
N24-0943
  • ‒ → Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.
 
A24-0094
  • ‒ → Check wiring for open circuit between test box and 4-pin connector referring to current flow diagram.
         Contact 1 and test box socket 112
         Contact 3 and test box socket 113
         Wire resistance: max. 1.5 ω
  • ‒ Additionally check wires for short to one another, to vehicle earth and to battery positive.
         Specification: ∞ω

If no wiring fault is detected and voltage was present between contacts 2+4:

  • ‒ Replace engine control unit
    => Page 24-121 .
 
N28-0134

Checking secondary resistance

  • ‒ → Check the secondary resistance on terminal 4 between
         Cyl. 1+Cyl. 4,
         Cyl. 2+Cyl. 3.
         Specification: 4.0... 6.0 kω (at room temperature)

If the specifications are not attained:

  • ‒ Replace ignition transformer (N152)
    => Page 28-4 , item 4 .

Power unit > Simos injection and ignition system > Ignition system, glow plug system > Servicing ignition system > Checking ignition transformer

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