Ignition system - general information and precautions

Engine electrical systems / Ignition system - general information and precautions

General
The ignition system includes the ignition switch, the battery, the crankshaft speed/ position sensor, the coil, the primary (low tension/LT) and secondary (high tension/HT) wiring circuits, and the spark plugs. On models with automatic transmission, a separate ignition module is also fitted, its functions being incorporated in the ECU on models with manual transmission. The ignition system is controlled by the engine management system’s Electronic Control Unit (ECU). Using data provided by information sensors which monitor various engine functions (such as engine speed and piston position, intake air mass and temperature, engine coolant temperature, etc.), the ECU ensures a perfectly-timed spark under all conditions (see Chapter 6). Note: The ignition timing is under the full control of the ECU, and cannot be adjusted - see Section 8 for further details.

Precautions
When working on the ignition system, take the following precautions: (a) Do not keep the ignition switch on for more than 10 seconds if the engine will not start.

(b) If a separate tachometer is ever required for servicing work, consult a dealer service department before buying a tachometer for use with this vehicle - some tachometers may be incompatible with this ignition system - and always connect it in accordance with the equipment manufacturer’s instructions.

(c) Never connect the ignition coil terminals to earth. This could result in damage to the coil and/or the ECU or ignition module (whichever is fitted).

(d) Do not disconnect the battery when the engine is running.

(e) Make sure that the ignition module (where fitted) is properly earthed.

(f) Refer to the warning at the beginning of the next Section concerning HT voltage.