Try this----------

While measuring the +5v line, unplug each of the affected sensors one at a time incl the oil pressure sensor(the low-oil lamp is +12v. so that won't affect the test) - the +5v should return after you disconnect the failed sensor

Alternately, first unplug all the associated sensors then measure the +5v line to see if it is good - if not good with all sensors unplugged, the problem is in the FCM\Gateway, it's connector, or the wiring harness or connectors

I'll be back.......................

As I tho't, Front Control Module info, wiring, and connection is in the '05 KJ Diesel Powertrain Manual, but not the KJ Service Manual, which is for the gasoline-fueled versions - both versions are available on the Colorado website - look in the FSM INDEX for specifics direction

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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

At last we have solved the mystery on "MY" Jeep. We put a new oil sending unit in a few weeks ago and it ran fine. Recently it shorted out the 5 volt reference of the FCM. So I recommend if anyone is having a similar problem (Water in fuel, fuel level sender, oil pressure, AC High Pressure/Low pressure). Check for 5 volt sensor supply out of the FCM pin #16 (brown and light green wire). If it reads anything less than 5v start at the: 5v Brown/light green line on the A/C pressure Transducer
FCM (Gateway module)controls, remove the connectors at the following locations; the fuel level sensor, low oil pressure light, A/C pressure sensor, generator/alternator field control, and Water In Fuel Sensor. Hope this helps someone else as I have spent way to much time chasing gremlins on my Jeep.

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2005 KJ Limited 4X4 2.8L CRD
EHM,
no F37 Recall
Timing Belt Change at 76,000 miles (10 years old)
GDE FT ECO tune
Samco's (Red)
FCV Elbow Kit
Removed FCV/EGR/Cooler and all coolant hoses on driver side
No Muffler, Cat only and 2 1/2" straight pipe
86k miles (Original Owner)
Build Date Apr/05

If you are having this problem check this thread as well viewtopic.php?f=5&t=80457&start=0

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2005 Liberty CRD, 245/75R16, OME CRD Springs front, OME HD rear

Excellent, thanks. These other two threads are exactly the symptoms my CRD is having. I'll dig through those sensors next weekend and post what I find.

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JDRoalkvam
Western WA