Ignition HT coil - removal, testing and refitting

Removal

1. Disconnect the battery leads.

2. Disconnect the LT wiring connectors from the coil, noting their correct fitted positions (see illustration).

Disconnecting a coil LT lead (1.8 litre model shown)

3. Disconnect the HT lead from the coil. where necessary, also disconnect the wiring connector from the ignition module (see illustration).

Ignition module wiring plug

4. Undo the retaining bolts and remove the coil from the car. If necessary, undo the clamp screw and remove the coil from its mounting bracket (see illustrations).

Removing a coil securing bolt

br> Undoing the coil clamp screw and nut

Testing

5. Testing of the coil consists of using a multimeter set to its resistance function, to check the primary (LT '+' to '-' terminals) and secondary (LT '+' to HT lead terminal) windings for continuity, bearing in mind that on the four output, static type HT coil there are two sets of each windings. Compare the results obtained to those given in the Specifications at the start of this Chapter.

Note the resistance of the coil windings will vary slightly according to the coil temperature, the results in the Specifications are approximate values for when the coil is at 20ºC.

6. Check that there is no continuity between the HT lead terminal and the coil body/mounting bracket.

7. If the coil is thought to be faulty, have your findings confirmed by a Vauxhall dealer before renewing the coil.

Refitting

8. Refitting is a reversal of the relevant removal procedure ensuring that the wiring connectors are correctly and securely reconnected.