Liberty Malfunction light

jzjohnz · #1 (**permalink**) 10-21-2009, 12:51 PM

My 2006 Liberty (V6/Auto/35k miles) Malfunction Indicator Light (aka check engine light) has been steadily on for ~24 hrs. According to the owner's manual, it's not serious until the light begins blinking, then, they say, have the dealer check it very soon.

My question is, is there a way to find out why it's on without going to the dealer or a mechanic? Owner's manual says it could be as simple a problem as poor quality gas or a loose gas cap, but the gas I'm using (Sam's) has not caused a problem up to now and the gas cap seems to be working fine.

I need to figure a way to download the code so I can see for myself what is causing this without the added expense of having the dealer rip me off.

Thanks....

SteelHeadz · #2 (**permalink**) 10-21-2009, 01:06 PM

Try this. Sometimes the DTC will display at the end of this test. Just follow the procedure..
1.Begin the test with the ignition switch in the OFF position.2.Depress the odometer/trip odometer switch button.3.While still holding the odometer/trip odometer switch button depressed, turn the ignition switch to the ON position, but do not start the engine.4.Release the odometer/trip odometer switch button.5.The instrument cluster will automatically begin the actuator test sequence, as follows: a.The cluster will turn ON, then OFF again each of the PCI data bus message-controlled indicators to confirm the functionality of the indicator and the cluster control circuitry:b.The cluster will sweep the needles for each of the gauges to several calibration points in sequence to confirm the functionality of the gauge and the cluster control circuitry:c.The cluster will sequentially step the odometer/trip odometer VFD unit display from all ones (111111) through all nines (999999) to confirm the functionality of all VFD unit segments and their control circuitry, then display the software version number.d.The cluster will generate five (5) chime tones to confirm the functionality of the audible tone transducer and the control circuitry.6.The actuator test is now completed. The instrument cluster will automatically exit the self-diagnostic mode and return to normal operation at the completion of the test, if the ignition switch is turned to the OFF position during the test, or if an electronic engine speed message indicating that the engine is running is received from the PCM over the PCI data bus during the test.

jzjohnz · #3 (**permalink**) 10-21-2009, 01:29 PM

Thanks Steel. Will this test preserve the odometer figures (as in total mileage & trip mileage) when the test is complete?

SteelHeadz · #4 (**permalink**) 10-21-2009, 01:30 PM

Quote:

Originally Posted by jzjohnz

Thanks Steel. Will this test preserve the odometer figures (as in total mileage & trip mileage) when the test is complete?

Yes Sir..

54cj3b · #5 (**permalink**) 10-21-2009, 09:17 PM

any auto part store could check it for you also with there little hand held comp

jzjohnz · #6 (**permalink**) 10-22-2009, 12:26 PM

Thanks 54cj. Probably have to do that since I ran the test that Steel gave me and it yielded no DTCs.

jzjohnz · #7 (**permalink**) 10-30-2009, 04:05 PM

Took my vehicle over to Autozone and had them use their DTC unit to find problem. Came back with 4 possibilities for light:
1) defective, loose or missing fuel cap.
2) EVAP canister broke, hose cracked or not connected.
3) Purge or vent solenoid defective.
4) vacuum leak at engine.

Don't think it's the gas cap because the highway performance has deteriorated on acceleration and uphill grades. Seems to be a vacuum leak somewhere and it'll be fun trying to locate it.

If you can help me narrow it down further it would be appreciated. For instance do the EVAP canisters go bad on these vehicles sooner than they should?

SteelHeadz · #8 (**permalink**) 10-30-2009, 04:51 PM

The evap canister is the least of the possible culprit.. I would check the vac. lines from the engine first , particularly the one that goes to a Tee that has a green cap on it.. This is the Evap. test port. Inspect the rubber hoses spliced in between the hard plastic lines very carefully. They tend to expand and crack and will cause an Evap dtc. Replace them with the same size and type as nescessary.

jzjohnz · #9 (**permalink**) 10-31-2009, 03:46 AM

Went looking for the canister a while ago and couldn't find it. Seems like it's down below the passenger side fender well where the windshield washer reservoir is. Otherwise, I couldn't locate it. Also, while I was at it I couldn't locate the spark plug wires on this thing either. Does it even have any?

HotRodOil · #10 (**permalink**) 11-06-2009, 09:24 AM

If it is like the earlier models, the canister is located Forward of the gas tank, above the rear axle. Lay under the rear of the vehicle looking up and you will see it. There are a couple hoses that go into it and one of them is prone to failure. I have repaired two of them on two different KJ's. If you see cracks in it, its bad.

SteelHeadz · #11 (**permalink**) 11-06-2009, 09:49 AM

Yup!
The EVAP canister (1) is located near front of fuel tank and next to the left/rear spring perch (5).

The 3.7, 4.7 and 5.7 engines uses a C.O.P.(coil on plug ) system.
Each coil (1) is mounted directly into the cylinder head and onto the top of each spark plug. This eliminates the use of ignition wires and gives it a more positive ignition performance .

jzjohnz · #12 (**permalink**) 11-08-2009, 10:42 AM

Thanks for the help and information fellas. This really helps as this is probably where the leak is.

Oh! I almost forgot to thank SteelHeadz for the pictorals, especially the spark plug information.

jzjohnz · #13 (**permalink**) 11-12-2009, 10:26 PM

I'll post an update as soon as I take the time to crawl underneath the vehicle and snoop around the canister area looking for leaking hoses and such. I'll let you all know what, if anything, I find.

jzjohnz · #14 (**permalink**) 11-19-2009, 02:21 PM

The light went out by itself the other day (assuming it's not burned out) during a short 40 mile highway trip. I've taken this trip several times since the light first came on and it didn't affect the light. I still think I have a vacuum leak in that area because even on the slightest slope I'll have to add more gas peddle resulting in a significant downshift....doesn't seem normal.

Could this be a faulty canister, or canister valve, that leaks intermittently?