I have a 1998 VW Jetta. I washed the car and engine this past weekend and now my car is running pretty rough (and the check engine lite is now on). I took it to a firestone & they told me that the Air Intake Sensor must be replaced. After leaving Firestone the car is running normal again (except the check engine lite still is on). My question: should I still replace the sensor or would I be ok to re-set the check engine lite? The quote from Firestone is $285! Any suggestions or advise is much appreciated!
Was a code scanner used to narrow the field?
If you have the code (letter(s) and numbers, post them here for further help. (I know you said THEY told you x,y and z)
You can reset the light, but if the sensor IS faulty, the light will return.
Damn, I wish I knew. I have no idea what the numbers or letters that were posted on the scanner. All they said is that the sensor must be changed. The car is totally running fine now, and I am hoping that I can just re-set the check engine lite. If I do that & the sensor is bad, like you said that the light will come back on and at that point I would be more than happy to replace the sensor, but I would like to re-set the light first. Do you know how to do that on a 1998 Jetta (2.0 Wolfberg Ed.)???
Just went to AutoZone & they gave me a code of P0103? I read & was told that I can buy a claener for the sensor?
Is this the Hot Film type sensor?.
If so, I might try cleaning the gunk out of the little internal passage in it. It has a little “Z” like passage through it. Like this one;
Also clean any oil gunk off the housing, particularly the debris screen.
What to use to clean it, I might try acetone or “GOOF-OFF” or IPA, Moonshine if available.
If the problem fixes itself the light will go out eventually.
Before replacing your MAF, lets try something else.
Running rough and engine light could have been wet spark plug wires, or Limp mode. I am guessing that the code P0103 is at MAF sensor code. It is usually possible to clean it. The AutoZone people likely had a suggestion for a cleaner. I have heard of people using all kinds of cleaners on it. The only real trick is to use something that will not leave a residue. I suggest a zero residue electronics cleaner spray.
When was the last time you replaced the air cleaner? Have you or someone checked the one you have by looking at it? Any time that air cleaner box is opened up it is wise to replace the air cleaner. If it has a K&N oiled filter in there, take it out and put a stock filter in there. Those K&N filters are famous for causing this kind of problem, unless they are serviced just right every time.
None of this will fix it if the MAF is actually damaged or if the plug is loose etc. but more often than not, a cleaning works.
NEVER replaced a sensor, or other part, based SOLEY on a DTC code. The DTC code only tells you WHAT the problem is with a CIRCUIT. It DOESN’T tell you how to fix it. You use the diagnosis it give you to find a way to fix it. For every DTC code, there is a troubleshooting procedure to find the cause.
ANY mechanic who doesn’t follow a troubleshooting procedure, before changing a component, is doing you an EXPENSIVE DISERVICE.
The DTC code P0103 is, “Mass, or volume, air flow circuit [has] high [voltage] input [to the engine computer]”. A dirty MAF sensor can cause the voltage to the engine computer to be high.
The auto parts store has a spray cleaner especially for the MAF (Mass Air Flow) sensor. Ask for it, AND clean the rest of the air intake tract (throttle body & throttle plate) while you’re at it with Carb/Throttle Body Cleaner. These components could use this cleaning even if there were no DTC code, because of the high mileage.
Thanks everyone for their comments. I ended up replacing the Master Intake Sensor.