Mysterious Check Engine Light

Here’s a fun one…

Last week, I was driving to my family’s house for the thanksgiving holiday. My 2003 Jeep Liberty with 87,000 miles on it was a little dirty, so along the way, I pulled into a drive through car wash to get it cleaned. Did the deluxe cleaning - wash/wax, the whole bit.

As my car was going through the car wash, my check engine light came on, and stayed on, though the car was running fine.

Several days later, I was in Boston visiting my girlfriend. I was driving down a street on my way home, looking for an entrance ramp to the Mass Pike. I came to an intersection, and realized I wanted to turn left, but wasn’t in the correct lane.

Nobody was behind me, so I put it in reverse and started backing up, so I could pull into the correct lane.

As I backed up, the whole car just died. I put it in park, and it started right up again, and the check engine light was off!

Question - what could I possibly have done to reset my car’s computer and make the check engine light go off? And furthermore, what in the car wash would have made the check engine light go on???

It Was The Car Wash. Jeeps Are Associated With Off-Roading And Supposed To Be Dirty.

Seriously, you should have had the Jeep checked for DTCs (dignostic trouble codes) shortly after the “Check Engine” light illuminated. Most large chain auto parts stores will do this for free in their parking lot. You could try now and see if any codes linger or wait till next time. The codes are self-clearing if the problem was temporary (glitch).


Hmmm, drove for a week with the CEL on and didn’t get it checked. Now that it’s gone off wants to know why it came on. Sorry but if it’s off that boat already left, unless you can get a hold of a code reader that will pull codes from history. My best advise is stop ignoring the CEL and get it checked while it is still on. Most larger auto parts chain stores will either read the code for you or let you use the code reader free.

Why leave it as a mystery? Get the code or codes read and post them here (the five character code, not the description). Even though the light is off now, if you do it soon the code(s) will still be there.

There Once Was A Man From Nantucket. When His MIL Came On He Said . . .

There are Chrysler bulletins on certain vehicles, including 2003 - 2005 Liberty automatic models pertaining to moisture in the transmission solenoid/pressure switch, illuminating the MIL (malfunction indicator light or “Check Engine” light) and storing various transmission codes. The fix if it has been contaminated (signs of moisture) is a new switch and 10-way wiring pigtail harness (Parts + a few hours labor).

There’s another bulletin about a solenoid switch valve, but we won’t go there (it’s on the valve body) and not moisture related.

Anyhow, see if you get any transmission codes next time and you’ll have an idea what it might be. It will need diagnosing and inspection.


Your computer will store the trouble codes until someone clears them. Have the codes read (most parts stores) and you will know why the CEL came on…But if the light has gone out, why bother?? You didn’t care about the light when it was on, why worry about it when it’s off??

Good one.

Geez guys…a strip of black electrical tape over the light will take care of all of that!

The check engine light will also hold a transmission code if severe enough, sounds like that was the case, possibly the TCC solinoid, only way to verify is to get a scanner hooked up to you ECM or PCM, TCM, check History codes your mystery should be revealed in your own cars Modules.