1. Oxygen sensor: The oxygen sensor monitors the amount of oxygen in the exhaust gas and helps the engine control unit (ECU) adjust the air-fuel mixture. A faulty oxygen sensor can cause the engine to run rich or lean, which can lead to increased emissions and decreased fuel economy.
2. Catalytic converter: The catalytic converter helps to reduce emissions by converting harmful pollutants into less harmful substances. A damaged or clogged catalytic converter can cause the check engine light to come on.
3. Mass air flow sensor: The mass air flow sensor measures the amount of air entering the engine. A faulty mass air flow sensor can cause the engine to run rich or lean, which can lead to increased emissions and decreased fuel economy.
4. Coolant temperature sensor: The coolant temperature sensor monitors the temperature of the engine coolant. A faulty coolant temperature sensor can cause the engine to run too hot or too cold, which can lead to decreased fuel economy and increased emissions.
5. Knock sensor: The knock sensor detects knocking or pinging noises in the engine and helps the ECU adjust the timing of the spark plugs to reduce these noises. A faulty knock sensor can cause the engine to run roughly and can lead to decreased fuel economy and increased emissions.
6. EGR valve: The EGR valve helps to reduce emissions by recirculating a small amount of exhaust gas back into the engine. A faulty EGR valve can cause the engine to run roughly and can lead to increased emissions.
7. Loose gas cap, or EVAP system error.
When the gas cap is not on properly, fuel vapor can escape and be detected by the vehicle’s EVAP system. This system is designed to catch fuel vapor and prevent it from entering the atmosphere, but if it detects a leak, it can trigger the check engine light.
If the check engine light is on in your 1994 Suzuki Sidekick, it is important to have the vehicle diagnosed by a qualified mechanic to determine the cause and have the necessary repairs made. Driving with the check engine light on can lead to further problems and increased repair costs.
