Check engine light on... why?

Hey all,
I've sold my '08 JK for an '01 XJ (had it about a month). I love it and don't miss the JK.

Today I started up the XJ and my check engine light went on. All the gauges are reading ok (oil, volts, temp) so I know the belt must be on. I haven't popped the hood yet cause I rushed in to work.

Any ideas what it might be, or how I can diagnos the issue?

I do have a Rusty's intake and spacer.
Thanks.

That year is OBDII. You can take it to a shop and have the codes read. If you trust Auto Zone scanners the employees can go out to your Jeep in there parking lot and read them for free. I feel that the shops read the codes better and not give you a generic reason that the light is on. Just my 2cents

Most auto parts stores rent or loan out their OBDII code scanner. You can read your own codes and the store will often give you print out of the codes or you can search OBDII trouble codes on the Internet.

Wiil the "Key on, Key off, count the flashes" method work for him? (it does on my '96)

That year is OBD I, not II. '96 up is II.

Once you have the code, don't automatically assume it means that something is broke.
The computer simply compares the signal voltage to what's programmed as normal. Out of range triggers a code.

Voltage drop from corrosion, unknown modifications, out of adjustment sensors, even the gas cap loose triggers codes on cars (that last is common with OBDII.)

With the code pointing out what circuit, you still have to diagnose the problem with the symptoms and further checks. Replace nothing unless you have good evidence it's bad, especially sensors. Most electonic parts are bought without any idea they are bad - just a desperate owner trying anything that might work. And they are not returnable by Federal Law.

Which means open the box you get and refuse it if installed previously. Some counterman fail to check, and old parts in the box is a common scam on them.

These days, a good Volt/Ohm meter is more important than a pair of pliers and a screwdriver.

TiRod said:

That year is OBD I, not II. '96 up is II.

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Who are you talking to? :dunno:

1997 will display codes with the key trick. Maybe some 1998's. 1998-2001 need the code reader to get the codes to output.

Pull codes however you can get em and post here for input and help in deciphering them....

Tim_MN said:

1997 will display codes with the key trick. Maybe some 1998's. 1998-2001 need the code reader to get the codes to output.

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What is the Key Trick?