Camry 2.4L 4-Cyl., Camry Solara 2.4L 4-Cyl., Celica, Corolla, ECHO, Highlander 2.4L 4-Cyl., Matrix, MR2, Prius & RAV4
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.
Conventional distributor and pick-up coil have been replaced by camshaft position sensor and crankshaft position sensor. Camshaft position sensor may also be referred to as Variable Valve Timing (VVT) sensor. 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. On Camry, Camry Solara, ECHO, Highlander, Prius and RAV4, camshaft position sensor is located on end of cylinder head at flywheel end of engine. On Celica, Corolla and MR2, camshaft position sensor is located just above intake manifold on cylinder head, at flywheel end of engine. On all models, crankshaft position sensor is located on front of engine, near crankshaft pulley. For knock sensor location, see KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
ECM uses 4 ignition primary control signals to ignitors for ignition coils. DIS uses 4 ignition coils with internal ignitors, one ignition coil for each cylinder. See Fig 1. Cylinder No. 1 is front cylinder at timing chain end of engine and cylinder No. 4 is rear cylinder at flywheel end of engine. ECM monitors IGF circuit at ignitor to ensure ignition coils have fired.