Car Computer Diagnostics, Codes & Electrical Sensor repairs.

My car says "Check engine" light is on. What do I do? Can I ignore it?

If you don't want to throw away your good gas mileage or risk being stranded someday, you will get your cars computer hooked up to Auto Computer system scan machine like what you will see below here in Deland.

BELOW: A Snap On brand of computer for electrical and sensor diagnosis for cars and trucks with on board computers. Also known as Engine control units (ECU) OR Powertrain control module (PCM) to professionals, and automobile/car computers to the general public.

A car computer is a designated computer that was developed to manage the engine and driveline components.

In the old days, automobiles didn't have onboard computers and they were easier to fix. The downside was that without them the autos were much less efficient and created much more pollution. Our Federal Government didn't like that.

In the 1990's auto manufactures began putting on board computers onto the new autos to improve vehicle efficiency, better fuel mileage and to reduce emissions as the Federal Government was now mandating for improvements.

However now when things went wrong with the car, the shade tree mechanics could no longer fix them properly without computer diagnostic code scanners. Now it required professional mechanics with specialized training and new computer code scanning tools.

Before we scan a vehicle for malfunction codes, 1st we look at the fuses and relays to make sure they are all in proper working order.  No need to go looking for a expensive complex problem when it can be a $1 fuse that can be replaced in 1 minute.

Now we plug the diagnostic computer into the cars onboard computer. Sometimes the connector is under the dash, and other times its under the hood.

These diagnostic computers are very sophisticated and capable these days. We have to tell it, what brand, what make, what model, what year, what engine and other information so the diagnostic computer will know with precision exactly which auto it is examining.

Once it knows what it is looking for, then it will communicate with the cars onboard computer very well.

The vehicles on board car/computer controls and monitors dozens of functions and processes these days. Along with telling the car what to do, it also records what was done within parameters, what was done outside of parameters and what is not functioning at all.

It actually remembers which auto components are refusing to communicate (broke totally) with the onboard computer along with which are out of operational parameters (misbehaving).

Once we have access to this information, we know with precision where to go hunting for the malfunctioning component. Sometimes the onboard computer will even tell us precisely which component is dead.

Vehicle onboard sensors send data to the cars onboard computer which then controls many functions of the cars operational characteristics.

1. There is a sensor which monitors exhaust gases called an oxygen sensor/AIR TO FUEL RATIO.

   ---

2.   There is a sensor that monitors how much air is entering the engine, called a mass flow sensor/MAFS or MASS AIR FLOW SENSOR.

   ---

3. WATER TEMPERATURE SENSOR.

   ---

4. AMBIENT AIR SENSOR.    There is a sensor that monitors the air temperature that is entering the engine/AMBIENT AIR SENSOR. Ambient air temperature or (IAT), intake air temperature measures temperature of the air going into the engine so that the computer can calculate the density of the air to determine the amount of fuel that will need to be added.

5. ---

6. There is a sensor that monitors the precise position of the throttle or gas peddle/Throttle Position Sensor (TPS) + Rubber Water Shield.

   ---

7. Engine Camshaft Position Sensor Connector & CAMSHAFT POSITION SENSOR.

   ---

8. Crank Position Sensor: A crank position sensor is an electronic device used in an internal combustion engine to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control ignition system timing and other engine parameters. Before electronic crank sensors were available, the distributor would have to be manually adjusted to a timing mark on the engine.
   
   The crank sensor can be used in combination with a similar camshaft position sensor to monitor the relationship between the pistons and valves in the engine, which is particularly important in engines with variable valve timing. This method is also used to "synchronize" a four stroke engine upon starting, allowing the management system to know when to inject the fuel. It is also commonly used as the primary source for the measurement of engine speed in revolutions per minute (RPM's).
   
   Common mounting locations include the main crank pulley, the flywheel, the camshaft or on the crankshaft itself. This sensor is the most important sensor in modern day engines. When it fails, there is a chance the engine will not start, or cut out while running.

   ---

9. There is a sensor that monitors the drive shaft speed so an electronic speedometer knows how fast your vehicle is going. You can even tell the cars onboard computer what the tire size is you are running on your car so it can adjust the speedometer output to match and be accurate. Trans Output Shaft Speed Sensor- TRANSMISSION OUTPUT SENSOR.

   ---

10.   EGR Pressure Sensor.

    ---

11. Purge Flow Sensor.

    ---

12. Town Car Rear Air Leveling Suspension Height Level Sensor.

    ---

13. Lincoln Town Car Rear View Mirror with DIMMER SENSOR!

    ---

14. sorry, no picture...WINDSHIELD WASHER RESERVOIR FLUID LEVEL SENSOR

    ---

15. ABS Rear Wheel Speed Sensor.

    ---

16. SMP/STANDARD ALS160 Front ABS Wheel Sensor-ABS Wheel Sensor.

    ---

17. AIR BAG AIRBAG SENSOR/ LINCOLN TOWN CAR RIGHT LEFT AIR BAG CRASH SENSOR.

    ---

18. COOLANT TEMPERATURE SENSOR KIT

    ---

19. Idle Air Control Valve.

    ---

20. Lincoln Town Car Headlight Sensor. It will automatically dim my high beams to low beam when another on coming car gets close enough.

    ---

This list of sensors is by no means complete. These sensors just happen to be what's on my Lincoln Town car and there's still a couple I couldn't find pictures of.

Other brands of manufactures can have other sensors. HOWEVER the point is they are all sending data to the cars on board computer which is in turn controlling many functions of the car. The majority of these sensors are transmitting data to the car/computer so it can control the FUEL AIR MIXTURE RATIO, and the TIMING of which to fire the spark plugs.

The affordable Advanced mechanic is hooking up his diagnostic computer/code scanner to my Lincoln that is misfiring and acting up.

Now the diagnostic computer has been turned on and his computer is booting up/waking up.

On the drivers door is a tag or label that tells us what information his diagnostic computer will need to know about this car so it can accurately communicate and diagnose it.

The specially trained mechanic enters the necessary information into his diagnostic computer/code scanner. Then the onboard car/auto computer tells the diagnostic computer which sensor is not sending the proper data. And what data the car computer has received before in regards to a malfunction.

In this case my MAFS is not dead, but it isn't sending the proper consistent data to the onboard computer. My car computer can hear it, but cant understand what its saying.

  There is sensor that monitors how much air is entering the engine, called a mass flow sensor/MAFS or MASS AIR FLOW SENSOR.

So the parts not dead, but its not functioning properly. So, do you replace it with a new one? Or try to clean it and bring it back to proper functioning  life?

The labor is the same, but on one avenue your buying a new part that may not be necessary, and on the other avenue a few minutes labor may save you significant money not having to buy a new part. Or you may spend a few minutes cleaning it to find out you still have to buy a new part.

Since buying a new part would entail leaving my car overnight so the part could be ordered and delivered, and cleaning it might get me out the door in 20 minutes (with my car), the mechanic recommended cleaning it and finding out if it improves the performance any before spending money for parts.

So here is how easy it was too clean.

1st we find it. Thanks to the qualified mechanic, he knew exactly where to look on this car. I didn't even know what I was looking for even after he told me it was my MAFS.

Now the mechanic unscrews the MAFS so he can examine its inner workings close up and personal.

This particular mass air flow sensor, is made up of two filament looking springs. The more air flow that goes past them, they stretch and change the electrical voltage that is flowing through them.

The onboard computer reads these voltage changes and knows exactly what that means.

However in my case (luckily) some grunge and dirt got in there and is coating these filament wires creating a minor short that is altering the voltage that's going through these wires so the onboard computer doesn't know what's going on as the readings are not within the specified HIGH/LOW parameters the computer is expecting. (Was I lucky because I didn't have to buy new parts or was I unlucky because it got dirty and needed cleaning?)

Its getting a signal but its not the right signals. A confused computer will hinder a automobiles performance.

So he sprays a very special cleaner on the sensor to carefully and gently clean the wires so there is no contaminates. He cant touch the filament with a scrub brush because it could stretch the filament and then the sensor would be destroyed as it could now never send the proper signal.

Time to put it back and recheck and run another computer diagnostic to see if the sensor is now sending the proper signals. If it works now, it will probably work for another 5-10 years. Of course there's no guarantees in that.

I was lucky. Now my MAFS sensor worked perfectly again. I was out the door in 20 minutes and took my Lincoln with me without having to buy any new parts. Don't you love saving money? Ok, maybe I don't love it, but I hate spending money.

ON ANOTHER NOTE:

I had complained to the mechanic that my throttle seemed to stick a bit when I 1st initially pushed down on my gas pedal. It only hung up in the 1st 10% of its movement. SPECIFICALLY it hung up only while leaving the idle position for more power.

I assumed the gas pedal or throttle linkage needed lubricating oil to free it up.

The mechanic went straight to the butterfly valve in my throttle body. He began cleaning the butterfly opening with powerful solvents. MY CAMERA DIDNT LIKE HIS FLASHLIGHT.

"WAIT" I was thinking. That's not oil lubricating my throttle connections. If they are sticky, they need lubricating. It just makes too much sense, doesn't it? Oil is for lubricating. Sticky need lubrication, right?       RIGHT???

Well its a good thing I'm not a mechanic. After the (REAL) mechanic removed the carbon build up that was holding the butterfly in place until you pushed real hard on the gas pedal, the resistance magically went away.

No oil, no lubrication. But the stickiness & resistance went away. I got my wished for result, but the mechanic didn't go down the road I was recommending to him. Good thing he was smart enough to NOT listen to me.

I could just imagine myself laying on my back under my dashboard spraying WD40 everyplace around the gas pedal and all its connections, including in my eyes (oh wouldn't that be fun), and not creating any improvements.

Then I would spray all the external throttle linkages outside the throttle body, and of course again I wouldn't gain any improvements.

So then I would buy new throttle cables and install them thinking that's the only thing left it could possibly be. And I would have been wrong on all of it.

I never would have thought a carbon build up inside my throttle body would cause the butterfly valve to stick while its in the idle position, closed position.

It took two minutes for the professional mechanic to clean the carbon off and it fixed the whole problem perfectly, without buying more parts, and without WD40 in my eyes.

All I can say is, no wonder I keep taking all my vehicles to Advanced Automotive Repair. I am so sick of paying all the other guys to milk me. And I'm tired of wasting money chasing my own best guesses, which typically are wrong.

But I still keep on guessing anyway as I let the professionals @ Advanced make the real decisions.

Who am I? I am a true honest to God customer of advanced automotive repair that was turned on to them by a recommendation of a friend who's opinion I trusted. They had happily used advanced for years.

After I became acquainted with their superior level of service above the competition, and after I saw how easily and willingly they saved me money, and I saw with my own eyes that they were honest hardworking people like myself, I became a true fan of theirs.  Then I began building their website.

That's who I am. A very happy customer of theirs and their website builder. Yup, that's me, just another white boy. Nobody special except in my own eyes.

My car radio died. It just quit working without any warning it was going to go on vacation. Again I got lucky. While my woman was at a yard sale, I spotted a factory Ford radio for $5. So I bought it. I wasn't positive it worked, but for $5 I could afford to be wrong.

With very special tools just for a Ford radio, the mechanic had my radio pulled out in 2 minutes. Clearly Ford makes their radios so an ordinary car owner can never change it out themselves. After seeing how the mechanic unlocked the radio so it slid out, I never had a chance.

He double checks all the wiring connections on the back to make sure the new radio will plug into my car.

Do you think that's the reason why my radio died? All the 2nd hand smoke it ingested? I couldn't say and if I could, I wouldn't admit anything.  

He hooks the wires up to my new radio before sliding and locking it back into its place. I didn't know radios slid in and out. I thought he would have to take apart my whole dashboard just to get to the back of it. Again, shows you how much I know.

Hey, I got lucky again. My new $5 radio works decently. That's a 500% improvement over my old dead radio.

All total, the mechanic had my new radio installed and working in less than 10 minutes. Yup, I'm a happy customer.