Except Altima

The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the engine. The ignition timing data is stored in the ECM.

The ECM receives information such as the injection pulse width and camshaft position sensor signal. Computing this information, ignition signals are transmitted to the power transistor.

During the listed conditions, the ignition timing is revised by the ECM according to the other data stored in the ECM:

• At starting.
• During warm-up.
• At idle.
• At low battery voltage.
• During acceleration.