Had spark plugs swapped out for 120k mile maintenance. Mechanic removed and reinstalled intake manifold to get to rear plugs. I’ve had a stored permanent Mass Air Flow Sensor code since (10 days). Code is P0102 - Mass or Volume Air Flow Sensor “A” Circuit Low.

There is no engine light on and car runs exactly as it did before the plugs were replaced. I’ve driven the car every day (roughly 10-25 miles per day).

Mechanic said that the code should clear itself and that if the CEL is not on that it’s not a big deal. There were a few other related codes which cleared within a few days but this one has stuck.

Q:
1. Shouldn’t the permanent code have cleared itself by now?

2. Does this require any attention or is mechanic correct?

 

Odd codes pop up when you disconnect the battery. Use your bluedriver to clear that code, recheck after a drive. That type of code should set quickly if it was real. Also you can check fuel trims and see if they’re in proper range.

 

I tried clearing with BlueDriver but get a message stating that permanent codes cannot be cleared. Also went back to mechanic. He tried clearing but again, no go. He said that he had accidentally started the car when the mass air flow sensor was not connected, hence the code. Two weeks of driving, still stored.

 

Hmmm, you may not be able to clear that individual code, you may have to do the “all clear” code erase, which resets all your emissions too …not a big deal, unless you have an inspection coming up real soon. What are your fuel trims and maf readings (in g/s) at idle? If fuel trims are normal and the maf is reading at or about 3.5 g/s at idle, you should be ok. Maf should read higher as you rev. Fuel trims should not change all that much with rpm if just sitting on your driveway.

 

imho it is a false positive which your advanced reader is showing. As long as your CEL is not lit up, you can ignore it.

If you are driven to see all clear on your reader, I would explore owner's manual or contact the customer service of the manufacturer of the reader.

Salim

 

In all honesty it’s not a big deal as long as I know that no damage is being done to engine/cat. I will give it more time to clear and check those readings. Thank you