I have code P0460 (fuel level sensor circuit malfunction, I think) coming up intermittently, I can clear it off and it stays off for a month or so and then comes on again, doesn't seem to make any difference in driving. I don't care much about it except that the CEL has to be off to pass smog check. Is this an 'important' code? Does it sense at the fuel tank, smog system, or injection pump? Suggestions on what to look at to fix it. I did a search and it seems to always be combined with other codes and maybe buss problems but this stands alone for me except for the glow plug code which I will be fixing soon.

Go to http://colorado4wheel.com/manuals/Jeep/KJ/ and grab a copy of the 06 FSM to search for the code. It says the voltage is either too high or too low which I would interpret to = voltage is out of expected range. Beyond that I can only speculate:
1. I don't think it's critical but it might impact the accuracy of your fuel gauge
2. I've see fuel gauge inaccuracy be related to a long in the tooth battery but not with a CEL - might check how clean the battery terminals are and the condition of your battery.
3. I have no clue where the plug in the associated wiring is that's shown in the FSM but if you can find it consider cleaning the plug terminals and making sure contact is good (ex. does wiggling the wire trigger the CEL).

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

Thanks, my fuel gauge seems as in/accurate as ever. But I have had battery issues, something draws down the battery when sitting and I now use a cutoff switch or leave it on a trickle charger when not in use. So maybe the battery system is effecting it.