The Check Engine Light (CEL) in your car comes on when your car’s CPU senses that something is wrong.  When it illuminates, the repair technicians at Earnhardt of Gilbert, a top Chrysler, Dodge, Jeep, RAM dealer in Arizona, state it is rarely an emergency situation but it is something you should bring in to have a mechanic evaluate soon.  In case your CEL goes on, here are the “top eight” reasons why.

The EVAP Purge Control Valve needs replacing

The Purge Control Valve is a part of the car’s EVAP system.  When your car’s engine is fully warmed up, the main CPU module gradually opens the purge control valve to allow the fuel vapor to be sucked from the charcoal canister and ported to the engine to be burned.

Spark Plug Wire(s) and Plug(s)

Faulty spark plug wires and/or spark plugs can prevent a cylinder from firing.  This can reduce your gas mileage and potentially damaging your car’s catalytic converter if it persists for too long.  If this symptom is happening to your car, then you likely need to replace the spark plugs and wires.

The EVAP Purge Solenoid needs replacing

The purge solenoid is part of your car’s EVAP system and helps control how much fuel vapor escapes into the atmosphere. The solenoid is controlled by the main CPU module and could be partially left open, a condition that will illuminate the CEL.

Mass Air Flow (MAF) Sensor needs replacing

The MAF measures the air coming into your car’s engine and works with the main CPU to determine how much fuel to inject into your car’s engine. When the MAF  sensor is malfunctioning, fuel economy will usually drop and the engine will run rough. This is a relatively common problem in older cars.

Ignition Coil(s) need replacing

Ignition coils provide high voltage to the spark plugs. High engine bay temperatures and age can result in the failure of ignition coils. Vehicle owners should pay special attention to this problem since, over time, ignition coil failure can damage the car’s catalytic converter.

Thermostat needs replacing

The thermostat is responsible for regulating the engine coolant temperature in the engine coolant system. When a thermostat fails, if often gets stuck  and fails to regulate the coolant temperature.  If the vehicle’s computer doesn’t see the engine coolant temperature  rising to the proper operating temperature, it will illuminate the CEL. The solution is to replace the thermostat.

Tighten the Fuel Cap

Believe it or not, your fuel cap needs to be tightened in order for your car’s EVAP system to function properly. If your CEL light ever comes on, the first thing to do is check that your fuel cap is on tightly! 

Oyxgen Sensor has gone bad

A very common car repair when the CEL illuminates is a bad oxygen sensor. The O2 sensor is extremely important to a car’s engine performance and can fail for a variety of reasons but usually it’s just a matter of age. They all seem to need replacement when a car gets over 100K miles or so.  If ignored, a faulty O2 sensor could result in as much as a 40-percent reduction in gas mileage.

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