Check Engine Light On.... And Then Off

[Doug Ram]

Had a perfectly awful day Friday. After getting the 2nd Covid shot Thursday I had to go to the doctor for a follow-up appointment for another condition, then more tests required a drive to another city. Get stung by a bee who was as surprised as I was to be in my car. After the doctor's appointment I get in the truck to drive out of town for the med tests... and the check engine light comes on. No messages and its not blinking. It's been only two days since the dealer replaced the front airdam, so I take a look and there's nothing wrong with it. Owner's manual says nothing about it being urgent, but I call dealer to get it checked. First appointment a week away. I take it and start my 50 mile drive out of town for the tests. 75% of the drive is interstate 70 mph. Two hours later I drive 60 miles home, mostly interstate. Yesterday I start up truck to run some local errands...... and.... HEY the Check engine lite is OFF!

WT....???

Have I gone thru a EcoDiesel regen?
Should I still go to the dealer and have them check the code?

 

[huntergreen]

I would let dealer read the code and see what’s going on.

 

[Doug Ram]

I called dealer, who told me that once the MIL light is off there won't be a fault code to read if truck's been turned on and off too many times. It's been 800 miles and the engine has been started and stopped at least 20 times since the light went dark.... They entered a note in the dealer maintenance system and told me to drive right in if it comes back any day they are open. A bit odd if you ask me...

 

[Ram_Bach]

Unless you are under warranty I would avoid the dealership like a plague. What they informed you is incorrect. Even if the light is off there are stored codes which will be time stamped at each occurrence. If you have any diy in you I recommend a Bluetooth type obd reader which are dirt cheap on the internet. Or take it to a parts store like O'Reilly auto or AutoZone. They can read codes too

 

[sirdumpsalot]

Correct. Second for buying a bluetooth OBD reader and look at the stored code yourself. I use the 'Car Scanner' app but there are multiple that will accomplish the same thing. You can even clear codes yourself once you fix the issue.