Ignition Coils, Checking
Ignition Coils, Checking
Checking primary connections and voltage supply
- Fuses for ignition coils OK (located in E-box in plenum)
- Remove bracket along with ignition coil power output stages -N122- and -N192-.
- Disconnect both 4-pin harness connectors.
- Switch ignition on.
- Connect one lead of VAG1527B LED voltage tester to engine Ground. Connect other lead in sequence to check for voltage at each pin of both 4-pin connectors.
LED must light up for all 8 terminals.
NOTE: The measurement is the voltage supply through the primary circuit of the applicable ignition coil to the power output stage.
If LED does not light for one terminal:
- Disconnect 3-pin harness connector from applicable ignition coil.
- Check wiring for open circuit between power output stage and ignition coil connector terminal 1.
Power output stage Ignition coil stage
4-pin connector terminal 3-pin connector terminal
Black connector Cylinder
1 1
2 4
3 6
4 7
Brown connector Cylinder
1 2
2 3
3 5
4 8
If wiring is OK:
- Check wiring for open or short circuit between ignition coil connector terminal 15 and fuse (E-box in plenum).
- Check voltage supply to fuse (open circuit).
If wiring is OK:
- Check ignition secondary circuit
NOTE:
- Measuring ignition coil primary resistance is usually not necessary with this test (primary resistance is approx. 0.3 - 0.5 Ohm, measured between ignition coil terminals 1 and 15).
- A high-tension isolation diode is integrated in the ignition coil secondary circuit. It is therefore not possible to measure ignition coil secondary resistance with conventional test equipment.
Checking ignition coil secondary circuit
- Connect multimeter US 1119 (Fluke 83 or equivalent) and check for open circuit between 3-pin connector terminal 4A and engine Ground.
If all Ground connections are OK:
- Replace ignition coils.
- Generate readiness code, Refer "Monitors, trips and/or Drive Cycle (Readiness Code)/Generating, Readiness Code" Testing and Inspection