crazyredj

Short question: Where is the odometer data stored? The gauge cluster or the computer?

My EVIC LED dashboard readout is so dim you can't see it in daylight. The odometer is fine, nice and bright. I want to replace the gauge cluster, but I can't get a straight answer about the odometer reading. Will a new gauge cluster be "plug and play," and thus display the mileage the computer tells it, or is the odometer data stored on the gauge cluster, making my Jeep appear to have whatever miles come on the cluster?

Thanks in advance!

crazyredj

REVISION: My "new to me" Jeep is actually a 2006! I'm a big dummy. But it works the same for 2005 and 2006, possibly 2007.

According to InstrumentClusterStore.com, odometer data is stored on both the ECM and the gauge cluster. Strangely, they do not communicate with each other. Thus, you can install any compatible gauge cluster as "plug and play," but it will maintain the source vehicle's odometer reading. If one were so inclined, it is possible to check the ECM odometer reading and compare it to that of the gauge—in which case you'd discover a discrepancy. It is also possible to have your "new to me" gauge cluster reset to match the actual mileage. A dealer will charge you an arm and a leg, and send your cluster off to be "officially" updated, complete with some "CERTIFIED" sticker to smack on the unit. InstrumentClusterStore.com will calibrate one they sell you for an additional charge of $100. If you know a mechanic with the right instruments (one who knew you well enough to be certain you weren't pulling an odometer scam), they might adjust it for you much more cheaply.

Pro Tip: Setting a for-sale vehicle's odometer to a lower mileage is a felony! I don't know about the mileage on your own personal vehicle.

94zj318

I would believe that the ECM controls the odometer, although data may also be stored locally in the cluster as well. I know that the WK's used a CANBUS system for MOST systems, which means the whole vehicle is essentially computer-controlled. The cluster can lose communication with the ECM, as our '05 WK did right before we traded it in. All of the gauges stopped working, and all lights on the dash came on. Plugging a scanner into the OBD-II port, I got a code of "Lost Communication with PCM". It still would keep track of mileage for some reason IIRC, though.

-Vince