Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Es300 & RX300
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 signals.
Two Variable Valve Timing (VVT) sensors and a crankshaft position sensor deliver input signals to ECM. VVT sensors may also be referred to as camshaft position sensors. ECM detects standard crankshaft position based on VVT sensor input signals and actual crankshaft position, and engine speed by crankshaft position sensor input signals. One VVT sensor is mounted in outer corner of each cylinder head, just below valve cover (oil filler cap end). Crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. For knock sensor location, see REMOVAL, OVERHAUL & INSTALLATION article.
ECM uses 6 ignition primary control signals to ignitors for ignition coils. DIS uses 6 ignition coils with internal ignitors, one ignition coil for each cylinder. Cylinder No. 1 is front cylinder on right side of engine when viewed from flywheel end of engine. Cylinder No. 2 is front cylinder on left side of engine when viewed from flywheel end of engine. Cylinders No. 1, 3 and 5 are on right side of engine. Cylinders No. 2, 4 and 6 are on left side of engine.
ECM monitors IGF circuit at ignitor to ensure ignition coils have fired.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.