Malfunction Indicator Light :(

[05Renegade]

Dear God,

this seems bad...


I don't know much about what it means...can anyone enlighten me?

What does in mean when it's on and can I fix it?

 

[jnaut]

There's actually a light labeled "Malfunction"?

 

[Warren.fischbeck]

Is it the check engine light?

 

[AlexKJ]

There's actually a light labeled "Malfunction"?

Isn't MIL (Malfunction Indicator Lamp) the proper name for the "check engine light"?

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Dear God,

this seems bad...


I don't know much about what it means...can anyone enlighten me?

What does in mean when it's on and can I fix it?

Relax... just read this thread

Good luck!

 

[george0029]

The "Malfunction Indicator Light" is the proper term for your check engine light.
It being on means the on board diagnostic system detected a problem with the vehicle.
Often this is a simple fix and can be done at home.

The first step should be to go to a mechanic or auto parts store and ask them to scan the code. You can also do it yourself, just look at the link AlexKJ posted. With that code you (or the forum lol) will be able to further diagnose the problem!

 

[jnaut]

The "Malfunction Indicator Light" is the proper term for your check engine light.
It being on means the on board diagnostic system detected a problem with the vehicle.
Often this is a simple fix and can be done at home.

The first step should be to go to a mechanic or auto parts store and ask them to scan the code. You can also do it yourself, just look at the link AlexKJ posted. With that code you (or the forum lol) will be able to further diagnose the problem!

Wow. Who knew? I mean, besides George and AlexKj...

 

[AlexKJ]

Wow. Who knew? I mean, besides George and AlexKj...

Hmmm... I think that may be like... anyone who has read their owner's manual...

[QUOTE='04 US KJ Owner's Manual, page 152.]8. Malfunction Indicator Light
This light is part of an onboard diagnostic system
called OBD II which monitors engine and automatic
transmission control systems. This light
will illuminate when the ignition is in the ON position
before engine start. If the bulb does not come on when
turning the ignition key from OFF to ON, have the
condition checked promptly.[/QUOTE]

Cheers

 

[jnaut]

Hmmm... I think that may be like... anyone who has read their owner's manual...



Cheers

I'm in the IT business. Spent one career as a software developer, am in the middle of another one as a Network administrator.

The last time I picked up an "owners manual" was probably 1979. What's your excuse? (popcorn)

 

[LibertyTC]

No one want's to explain the key trick, that aint in the manual.
Your digital odometer can read the stored Check engine codes by:
Without starting the Jeep:
Turn Key ...On-OFF-ON-OFF-ON (leave it the On position)
Should read a P00442 example write the code down, and post it back in here if you are not sure what it means.

 

[AlexKJ]

I'm in the IT business.

Me too!

The last time I picked up an "owners manual" was probably 1979. What's your excuse? (popcorn)

In that year I was not born yet... if you want an excuse for that, you'll have to ask to my parents! lol3.gif

 

[ThunderbirdJunkie]

ITBJRC 2005+ most 2005+ models had the BCM reflashed to disable the key trick for checking codes.

 

[HoosierJeeper]

That was 06 IIRC.

 

[ThunderbirdJunkie]

HJ can you still do the key trick?

on/off/on/off/on?

 

[george0029]

Wow. Who knew? I mean, besides George and AlexKj...

Sorry but considering OP didn't know what the MIL was, I chose the most basic explanation...

 

[Dave]

ITBJRC 2005+ most 2005+ models had the BCM reflashed to disable the key trick for checking codes.

I can check mine using the key trick and it works. I have a 5/05 build date so sometime after that build date they were reflashed maybe?

Dave

 

[hyde]

You can check the version of your firmware by holding down the odometer reset button in your dash and turn your jeep on (not run, just up to ON/ACC level) it will go through diagnostics and then end with firmware version.

Dave, you can post yours and he can compare to see if it is same version, then that will tell you if key trick will work or not. We know it works on all 04s for sure, but 05 is on chance basis..

 

[05Renegade]

Thanks guys.

My old car just had a "check engine" light.

Just making sure it wasn't a transmission issue cause I had it worked on recently.

Once again, Thanks guys.

I'll try the key trick to see what code I was throwing...

EDIT: The code number is P 0138 I believe thats an O2 sensor issue...

-Joey

 

[george0029]

Correct. 90% of the time it's just a bad o2 sensor and replacing it solves the problem. Careful when you're taking the old one out and replacing so you don't strip threads... Good luck!

BANK 1 SENSOR 2 is the sensor right behind the cat on the drivers side btw.

 

[ThunderbirdJunkie]

Correct. 90% of the time it's just a bad o2 sensor and replacing it solves the problem.

Incorrect. There are usually deposits from the engine running rich that lead to the O2 sensor not reading.

Not going to go any further than this because this stuff is tricky to diagnose over the internet.

05Ren, check your spark plugs. Or just replace them if you haven't; they probably need it anyway.

 

[LibertyTC]

Try to get sensor replaced and After the spark plugs, give the AIC (air intake control) and ports and throttle body a cleaning.
Consider replacing the air filter as well if it has not been done in a while.