Hi, I'm a new 06 liberty CRD owner and appreciate all the information and help on this forum

My CEL turns on when the ignition key is turned on and the CEL turns off before the engine is started
The CEL is also off when there is a fault code.
So,,,,either the previous owner flashed some patch that would cause the ecu to control the CEL in this manor or some relay or switch has been install in the CEL circuit. I've looked under the dash and nothing stands out as being non OEM

Has anyone heard of a patch that will cause the CEL is function this way?

Can someone help me find the wiring diagram for the CEL so i can better look for a possible hard wired relay that may have been installed to cause this "cheat"? on the CEL

Thank you
ian

There are code that don't turn on cel. Like bcm codes, maybe would be helpful to post your codes so who knows them can confirm if they are ecm, tcm or bcm. For example pulling out the viscous heater relay will not trigger a cel, but scanning the code with an obd2 scanner, would reveal the code that viscous is not working.

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.

Look at NOOB sticky thread for FSM

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2006 Jeep Liberty CRD Limited - Nov '14
GDE Eco Tune - Nov '14
Sasquatch Motor Sports Intake Elbow Kit - Jan '15
TB / WP / SAMCO Hoses - Dec '14 (93,000 miles)
Redline Synthetics (Frt/Rear Differentials) - Dec '14 (93,000 miles)

All EFI systems briefly energize the various lamps as operational check - wouldn't want to head out with a fault but the lamp was burned open, so didn't know the engine\drive-train was self-destructing right under my nose
- some are even smart enuff to sense the burned-out bulb and blink the whole instrument panel as warning, or\and invoke limp-mode

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'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

the lamp isn't burned out. the CEL lights up when the key is turned on
I was under the impression that the cel should stay on untill the engine is running

but my turns off before the engine is started

I had glow plug codes and the CEL never came on
I disconnected the MAF and the CEL didn't come on

Does your ABS light do the same thing? If there is no fault, all warning lights should light up when you turn the ignition on to do a bulb check, then turn off if you delay start for long enough.
John

Seems to me that the CEL light is working fine.....maybe you are lucky enough that the previous owner had a GDE tune installed that stops the MAF sensor setting a code when it is disconnected......not sure about the glow plugs though

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2002 Export CRD 2.5 Sport

the CEL turns off right away, the ABS light stays on for awhile
I had an emission test done. It came back with 5 DTC, 4 for glow plugs, 1 for the disconnected MAF
The test report indicated that the ECU was calling for the MIL(malfunction indicator light, same as CEL) to be on.
It was off

Thats why i suspect something hard wired into CEL circuit that is turning it off.
Am I missing something?
I'm new to owning a "modern" vehicle. I bought this for my wife as a trouble free "new" car
I drive an old '95 diesel with no ECU

In addition, IIRC, CEL flashes to prove operation, then shuts off unless a hard DTC is logged
- some DTC do not evoke the CEL
- DTC, CEL stays on when engine is running
- no DTC, CEL is off while engine is running, lites again if engine stops without key off - this to alert you to non-running condition with IGN on, for whatever reason

ABS is autonomous computer, takes awhile to boot, check it's peripherals, log-in, and wait for further, lite goes out
- ABS lite sounds correct
- it's the autonomy that causes problems when scanning the KJ intranet - ABS is not even a team player

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'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

Need to be pretty good on electronics to mess with the requests to switch on or off the MIL. I have been researching it a bit and have almost given up.
John

I found the wiring diagram, and appears that the CEL is integral to the instrument cluster

So any strange CEL functions must be from software changes

I will try and down load the program