Circuit Description
WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
ECM uses signals provided by crankshaft and camshaft position sensors. If engine speed rate has changed enough to equal a preset number, a misfire is detected and MIL is illuminated. If misfire rate is great enough, and driving conditions will cause catalytic converter damage or overheating, MIL blinks when a misfire is occurring. DTC is set during any particular 200 revolutions of engine during which misfiring is detected which can cause catalytic converter overheating and/or damage, or during any particular 1000 revolutions of engine during which misfiring is detected which can cause a deterioration in emission levels. Possible causes are:
- Open or short in wiring.
- Poor contact at ECM or component.
- Disconnect, blocked or damaged vacuum hose.
- Ignition system malfunction.
- Defective fuel injector(s).
- Improper fuel pressure.
- Defective Mass Airflow (MAF) meter.
- Defective Engine Coolant Temperature (ECT) sensor.
- Improper engine compression.
- Improper valve clearance.
- Improper valve timing.
- Defective ECM.