Hi All,
Jeep threw a u1421 code today, things I noticed that were weird were, a/c wouldn't work, over head display was displaying --(dashes) instead of numbers. I've also been having trouble with rough idle on startup (ignition turns over fine, just rumble, rumble, rumble, then smooth idle) about every 10th start. To remedy this (I hope) I have a new fuel filter head and filter coming in the mail (with the new bigger plug)...

I don't know if the two go hand in hand but figured someone out there might know something about this...

Thanks much!

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2005 Kahki Liberty Limited CRD (Early Build)
Provent, 245/70/R16 Yokohama Geolanders AT-S, GDE EcoTune, Fumoto Valve, Samco CAC Hoses, Malone Roof Rack, Funny looking Texas Brush Guard.
Residing in NorCal

The messages sent on the CAN bus are distinguished by an identifier (ID). Each CAN ID is defined to contain a certain number of bytes. The Transmission Control Module (TCM) verifies that it has received the proper number of bytes for each ID.

When Monitored:
Continuously with the ignition on, one valid CAN ID received at least once, and no U0002-CAN Bus Off Performance DTC present.

Set Condition:
When the TCM detects an incorrect CAN ID from the ECM/PCM.

check for any other dtc's in all other modules

check tcm connectors

possible replace & program tcm

Hope this helps.

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The only replacement for displacement is positive manifold pressure.

The code list that I have doesn't show it. Sorry.

Terry

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2011 Ford F-150 XLT 4X4

"U" means it's a network code.
"1" means it's a manufacturer specific code
"421" is the meat and potatoes.

I found this online:
U1421-IGNITION KEY OFF TIMER PERFORMANCE - TIMER TOO FAST
U1421-IGNITION KEY OFF TIMER PERFORMANCE - TIMER TOO SLOW

U1421-Implausible Ignition Key Off Time Received

The first two are 2001-2007 Daimler Chrysler diesel codes. But not specifically Jeep Liberty CRD codes. The third is a new Dodge (2007.5+) 6.7 Cummins code. These codes are all very similar. I have a feeling this will steer you in the right direction. Good luck.

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Spaghetti CRD
2006 Liberty Sport CRD 4x4 @150k miles
GDE Full Torque Tune
OME 2.5" Lift + JBA Upper A-Arms
IRO Upper Control Arm
245/75R16 BFG AT KO2's
OEM Skid Plate Set
Muffler deleted
Suncoast TC, MagHytec AT pan, TransGo Shift Kit
Sasquatch WEEKS Stage 1 & 2
Samco Hoses
ARB Rear Diff Cover
In-Tank Lift Pump

Just changed the glow plugs and control module with the GDE Glow plug update to the eco. CEL is not on but got that code when I check it with the scanner


Thank you.

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2006 CRD, 2nd Owner, GDE ECO, 5V steel fast-glow plugs, updated fuel-head

Bio-Diesel when/where I can. In Houston available at http://www.houstonbiodiesel.com/ and it conforms to ASTM. They also have home brew classes!!

60 % Suburbs N. of Houston, TX - Conroe / The Woodlands Area 40 % Colorado and the West