Why does your Toyota suddenly turn on the check engine light? The simple answer is that it encountered a condition that the onboard computer systems cannot correct – and so it’s warning you of a problem.
NOTE: if the check engine light is blinking, you should pull over when it’s safe to do so and turn off the engine. Tow the vehicle to a repair shop.
There are plenty of conditions that the onboard computers can handle. Modern cars are “self-tuning” – that’s why you rarely hear the term “tune up” anymore. Dozens of sensors monitor various subsystem and provide computers with information necessary to act. For example, mass airflow sensor measures air entering the engine, while the oxygen sensor measures the amount of un-burned oxygen in the exhaust - that information allows the ECU (engine control unit) to on-thy-fly adjust the air-fuel mixture that’s sent into the engine.
The check engine light can be turned on because one or more conditions occur that cannot be compensated for by the computers – and there are, literally, thousands of such conditions. Some are trivially simple – like the worn gas cap – it’s a physical issue that a change in electronically communicated parameters cannot fix. Another common one is a sensor failure. Worn out spark plugs are another example of a physical issue that computers cannot fix – spark plugs need to be replaced with new ones.
At Frank’s Auto Service in Walnut Creek we offer comprehensive check engine light diagnostics, and once we know the root cause, and obtain your approval, we will get your Toyota repaired and ready for the road. Call our Walnut Creek auto repair shop to make an appointment. All Toyota repairs performed by our technicians are backed by a nationwide 3 year / 36,000 mile warranty.