GS300 & Is300

The Distributorless Ignition System (DIS) uses Engine Control Module (ECM) for determining ignition timing (spark advance). 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. ECM detects standard crankshaft position based on camshaft position sensor input signals, and actual crankshaft position and engine speed by 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 & INSTALLATION - EXCEPT GX470 article.

The ECM uses 3 ignition primary control signals to ignitor for ignition coils. DIS uses 3 ignition coils to fire 2 cylinders simultaneously using same ignition coil. Cylinder No. 1 is front cylinder at front of engine. Cylinder No. 6 is 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 spark plugs on remaining cylinders. ECM monitors IGF circuit at ignitor to ensure ignition coils have fired.