URGENT: Got Check Engine Light + FordPass notification (Picture Inside)

[JimC]

I kept getting a CEL every time I used an underbody spray. After several visits to the dealership, and sensor replacements, they finally figured out it was a split in the wiring to the cat/O2 sensor. After replacing/repairing the wiring I haven't had the issue again.

Sponsored

 

[jboogie1289]

Interesting!!! I just received an Update almost addressing that same thing or really similar to that.

 

[kinelisch]

frankly, I scan the car, record the codes (scanner saves it as a file) and I clear the codes and tell the customer to drive the car and come back if the C.E.L. comes on

Too many times a car will just toss a code and it is a glitch.

If you went into a shop, and they charged you $180 dollars for a "diagnostic fee" for a code read and scan, you'd be buying a cheap code reader too just to be able to pull the codes and clear them, then see if they return.

Some codes will return, and that is when you go deep, but a code is not a diagnosis it is a symptom

Say you get a P0304 for a #4 misfire

Is it a plug? Tube? a leaky valve cover gasket letting oil into the plug well? Coil? Wire to coil? Bad driver in the ECM? bad injector? bad valve allowing air in/loss of compression? Leaky head gasket letting a little coolant in the cylinder that causes a misfire on start up/cold engine?

Are you looking at data like fuel trim making sure it is within just a couple of percent of where it should be?

An O2 code comes back pretty quick because the cat efficiency (P0420) is always comparing the upstream and downstream sensor and the sensors play a big part in adjusting the A/F ratios

With a good graphing scanner, and even some of the $50 dollar ones you can look at the sensor data and figure out if they are working by voltage and waveform

And you don't need a $3000 scanner to do this, a bunch of the cheap scanners show you this data

Very nice. Thank you.

 

[kinelisch]

Interesting!!! I just received an Update almost addressing that same thing or really similar to that.

wow very interesting. I didnt get that update..... Or I got it and didnt know.

 

[kinelisch]

So, quick update — I took the car to the dealer the same day for an oil change. They told me the Check Engine Light was triggered by the O₂ sensor detecting a rich condition. They cleared the code, and since then, I’ve driven about 80 miles with no light coming back on. Does this mean I’m in the clear, or can it take longer for the ECU and O₂ sensor to pick up the issue again?

 

[Zig]

So, quick update — I took the car to the dealer the same day for an oil change. They told me the Check Engine Light was triggered by the O₂ sensor detecting a rich condition. They cleared the code, and since then, I’ve driven about 80 miles with no light coming back on. Does this mean I’m in the clear, or can it take longer for the ECU and O₂ sensor to pick up the issue again?

It depends upon how the reset was performed. An inexpensive obd scanner should be able to determine the i/m state.

 

[Neggytive]

Glitch...

As I said above sometimes codes get tossed for no good reason

That is the reason I don't chase codes.

record the data, look at the basics while I am in there (fuel trims, voltages, O2 sensor switching, etc) and unless something is really screaming at me (Fuel trims at +35%!) or the car is talking to me by running rough (a quick look at the Mode 6 data for cylinder contribution and misfire counts) then I am going to clear the codes and ask them to drive the car for a day or so and bring it back.

If there is still an issue, then I will deep dive into it and look at all the codes, figure out what code is the real problem and which ones are created by the real problem, again a problem with one thing can cause a efficiency code not because the catalytic conv is bad but because the data is falling outside of the expected range, and that is the difference between replacing $4.50 of leaky cracked vacuum line and replacing a $1000 catalytic convertor.

If you were curious you could pull up the screen that has all the engine info on it and watch the A/F ratio, it really should never go richer than 12 to one and more likely you'll see when you are putting your foot into it it is more like 12.5 to 1 and that is on the stock tune.

If you had an E30. E85 or other Ethanol optimized tune in there the A/F numbers would be completely different as you need more fuel

 

[kinelisch]

Glitch...

As I said above sometimes codes get tossed for no good reason

That is the reason I don't chase codes.

record the data, look at the basics while I am in there (fuel trims, voltages, O2 sensor switching, etc) and unless something is really screaming at me (Fuel trims at +35%!) or the car is talking to me by running rough (a quick look at the Mode 6 data for cylinder contribution and misfire counts) then I am going to clear the codes and ask them to drive the car for a day or so and bring it back.

If there is still an issue, then I will deep dive into it and look at all the codes, figure out what code is the real problem and which ones are created by the real problem, again a problem with one thing can cause a efficiency code not because the catalytic conv is bad but because the data is falling outside of the expected range, and that is the difference between replacing $4.50 of leaky cracked vacuum line and replacing a $1000 catalytic convertor.

If you were curious you could pull up the screen that has all the engine info on it and watch the A/F ratio, it really should never go richer than 12 to one and more likely you'll see when you are putting your foot into it it is more like 12.5 to 1 and that is on the stock tune.

If you had an E30. E85 or other Ethanol optimized tune in there the A/F numbers would be completely different as you need more fuel

Very cool methods and thinking. Thanks for sharing that.

Sponsored