GS300 & SC300

The Distributorless Ignition System (DIS) uses the Engine Control Module (ECM) for determining ignition timing (spark advance). The ECM may determine ignition timing (spark advance) based on various input signals, engine RPM and knock sensor input signal.

Camshaft position sensor and crankshaft position sensor deliver input signals to ECM. The ECM detects the standard crankshaft position based on camshaft position sensor input signals, and the actual crankshaft position and engine speed by the crankshaft position sensor input signals. Camshaft position sensor is located on left rear intake side of cylinder head. Crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. For knock sensor location, see REMOVAL, OVERHAUL & INSTALLATION article.

The ECM uses 3 ignition primary control signals to the ignitor for the ignition coils. The DIS uses 3 ignition coils to fire 2 cylinders simultaneously using the same ignition coil. Cylinder No. 1 is front cylinder at front of engine. Cylinder No. 6 is the rear cylinder at flywheel end of engine. One ignition coil is mounted on top of spark plug on cylinders No. 2, 4 and 6. Spark plug wires are routed from ignition coils on top of spark plugs to the spark plugs on the remaining cylinders. The ECM monitors IGF circuit at the ignitor to ensure ignition coils have fired.