Check Engine is blinking or lit on the dashboard. Few people are optimistic about this. However, there is no reason to panic. The Check Engine light on the second-generation Ford Focus often lights up, but there is no tragedy in it. In almost 90% of cases, actuation of the emergency lamp is caused by trifling reasons, and it is possible to eliminate them with bare hands. Yes, sometimes there are serious breakdowns, but we will try to cover the widest possible range of faults in Ford Focus 2, which causes the check light.
Check Engine, what is it exactly?
Everyone probably knows what an engine check is: panic, cold sweats and a preliminary calculation of the repair losses. But let’s not be dramatic until we figure out the cause, and figuring it out without experience is hard enough. Why did the check light up?
The electronic engine control unit monitors hundreds of sensors on the chassis, body, interior and engine. As soon as it receives incorrect data, data which do not correspond to the ratings programmed in the computer memory, the ECU tries to solve the problem itself, without distracting the driver.
For example, the CO level in the exhaust gases has suddenly increased and exceeded the allowable 0.5%. The Ford Focus 2 self-diagnostic system immediately sends requests to the catalytic converter and fuel system sensors.
It reads their readings and, if everything is OK, adjusts the fuel-air mixture proportions to bring the exhaust to normal. But if at least one of the sensors does not respond, the system switches on a Check Engine light: sorry, brother, you have to deal with it. You have to figure it out.
Check lighted up, what to do
Don’t panic. On the old carburetor engines, this ominous light mostly signaled power and ignition system malfunctions, mostly carburetor malfunctions. But times have changed and electronic systems have become more and more common. So on today’s Ford Focus 2, the Check Engine can indicate any malfunction in these control system traffic – from a punctured high-voltage wire, to a failure in the exhaust gas recirculation system.
Somewhere in the field, a hundred yards away from civilization, we will not be able to make a qualitative diagnosis. Therefore, let’s consider the worst-case scenario – the field. We will go from simple to complex and if we are lucky, we will be able to find the cause of malfunction by ourselves, without complex diagnostic equipment. Let’s go.
Strange as it may seem, the Check Engine can light up even due to a low fuel level and even when the reserve check lamp has not yet thought to light up. It’s simple, we went too sharply into a corner, the car tilted, the float in the tank dropped and the system has already sent a signal to the ECU about the critical amount of fuel.
Solution: fill up a full tank (or at least more than half), the check should go off. In extreme case dump the minus terminal from the battery and put it on again. The error is likely to go away.
A low oil level also activates the light. Open the hood, let the oil drain and use the dipstick to check the level. If necessary, refill the oil, wait 15-20 minutes, start the engine and if it was in the oil, Check Engine will go off. This is if we do not have any problems with the engine – fuel consumption is normal, traction and dynamics are fine, nothing leaks or rattles, normal starting and no overheating of the engine.
Spark plugs, wires and ignition coil
Very often the check lights up or flashes when there is a miss in the spark formation. Our action:
- check the spark on all four cylinders;
- check the ignition coil, for this you need a multimeter;
- check the high-voltage wires for breakdowns;
- if you have a spark plug tester handy, great, check the plugs too.
This bouquet of troubles occurs most often after a heavy rain or a visit to a too conscientious car wash. And if you washed the engine the day before, there is no doubt at all, water got on plugs, coil and flooded wires. In this case the engine may be moving, there will be slackening at acceleration, idling is floating. It is enough to dry all this stuff, and the error will disappear. In the extreme case, you will have to replace plugs and high-voltage wires.
Fuel pump, filter and injectors
The problem of fuel quality in general is quite acute. The check can light up just because of the disgusting fuel, and it already causes failures in the whole army of sensors of the power system. Bad, dirty fuel can always be drained and refueled with a good one, but the injectors, filters and pump will have to be checked and cleaned separately, if necessary.
Check in order:
- clogged fuel filter reduces pressure in the ramp, so the ECU reacts to this glowing Check Engine light, the solution – replace the fuel filter;
- pump failures also cause a drop in pressure in the system, checking the fuel pressure in Focus is simple, but you need a pressure gauge for this;
- lack of fuel in the combustion chamber can be caused by the injectors themselves, output – washed injectors with their own hands, but it is better to do it on the service station stand, at the same time there will evaluate their condition and performance with high accuracy;
- the gas tank lid is not tightly closed, the most trivial reason, but it causes depressurization of the power system, pressure drop and Check Engine indication.
Другие датчики и катализатор
The catalytic converter and lambda sensors are often the cause of check engine light activity. The catalytic converter and lambda probes are often the cause of the check engine light. The catalytic converter is not eternal and has its service life.
It is easy to foresee the problem occurrence – usually the neutralizer can go about a hundred thousand kilometers, if the fuel was good, then even all 130. Consequently, if the mileage is high, the catalyst is likely to be the cause. This also applies to the oxygen sensors.
If the mass air flow sensor malfunctions, the error is sure to show up. It’s also not difficult to check the air mass flow sensor on the Focus. It will require only a multimeter and elementary knowledge of nominal values.
Resetting Check Engine on Ford Focus
Of course, this is not a solution to the issue, but this method can help to restore the status quo after the work is done in one direction or another. As we said before, it is enough to remove the minus battery terminal, and then put it back in place. The check will go out and not light up again if we have found and eliminated the problem.
Otherwise, our way will be to the diagnostic center for a complete and detailed check of the condition of the car. There we will accurately indicate the cause and prompt further action. Let Check Engine disturb you as rarely as possible, have a good road and good fuel!