A Jeep Liberty will not start, or it starts and stalls as soon as the security light flashes. KJ trucks (2002-2007) and KK trucks (2008-2012) both say Liberty on the tailgate. They do not take the same PCM, and the KJ itself was built with more than one engine.
A Wrangler module is a common wrong order because both are Jeeps from the same era. The Liberty calibration, the immobilizer, and the connector family are its own parts.
Here is how to match a Liberty PCM and what the security system is doing on a no-start.
Jeep Liberty PCM at a Glance
| Truck | Engines | Replacement rule |
|---|---|---|
| KJ, 2002-2007 | 2.4 and 3.7 | Match the engine. A 2.4 file will not run the 3.7. |
| KK, 2008-2012 | 3.7 | KK hardware and calibration. A KJ module is the previous generation. |
| Either one | Gas 3.7 or 2.4 | Not a Wrangler PCM, even from the same year |
The Liberty PCM is chosen from the label on the original module. The VIN confirms the engine and the immobilizer data.
KJ and KK
The KJ used the 2.4 and the 3.7. The KK kept the 3.7 and changed the module generation. A 2006 3.7 PCM and a 2010 3.7 PCM are not a matched pair because both engines say 3.7 on the cover. The part number is the difference you can see without guessing the year from the headlights.
Manual and automatic transmissions use different calibrations. Four-wheel drive content is in the VIN. Ordering "3.7 Liberty, automatic" is closer. Ordering from the label is the one that fits.
Security Light and a Crank-No-Start
SKIM Pairing
Liberty trucks use the Sentry Key immobilizer. The PCM has to share a secret with the SKIM module and the keys. A used computer from another Liberty still has that other Jeep's secret. It will crank, the security light will flash, and the engine will not stay running. Does a Jeep PCM need to be programmed is this step. On a Liberty it is SKIM pairing plus the VIN and the engine calibration.
When It Is Actually the Module
A PCM that fails in service tends to drop off the scan tool, set an internal fault, or quit driving fuel and spark while power and grounds at the connector are still good. One lean code or one cam sensor code is not that pattern. Clean the connector and confirm the ground path before a replacement, because a Liberty that has lived in the rust belt will put the same corrosion on the next module.
Not a Wrangler, Not a Grand Cherokee
A Wrangler PCM from the same year is the wrong vehicle. So is a Grand Cherokee module that happens to use a 3.7 in an earlier generation. Shared displacement is not a shared calibration.
KJ or KK, Then the Engine
A Jeep Liberty PCM has to match KJ or KK, then the 2.4 or the 3.7, then the transmission. After that it has to be programmed to the VIN and paired to the SKIM. A Wrangler part is a different Jeep.
Premium PCM pre-programs Liberty modules to the VIN with the immobilizer paired, and includes a free lifetime warranty.
Call 1-888-735-1564 or email support@premiumpcm.com with the VIN and the part number from the original PCM.
Frequently Asked Questions
Are KJ and KK Liberty PCMs interchangeable?
No. 2002-2007 and 2008-2012 are different module generations. Use the part number from the truck you have.
Will a 2.4 KJ PCM run a 3.7?
No. Match the engine on the original module label.
Can I install a used Liberty PCM and skip programming?
It will not start and stay running. The SKIM immobilizer has to be paired to this Jeep, and the VIN has to be written.
Will a Wrangler PCM from the same year work?
No. The calibration and the vehicle content are different. Order the Liberty part.