My 02 is throwing a 0837 code. The references say "P0837 Four Wheel Drive (4WD) Switch Circuit Range/Performance." described as "Four wheel drive (4WD) muxed switch input detected in invalid or irrational switch state (switch status provided to engine module from transfer case module during 4WD low gear engagements)"

So it is about as cryptic as Linux error messages.

Since my 4wd system seems to be working just fine I'm at a loss as to what it is that threw this code. The only problem I'm having with the KJ right now is an erroneous temp guage.

Any ideas?

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Matt Townsend
Sebastopol CA

02 Red Libby w/Frankenlift, Full armor incl AllJ stuff, 245 MTRs on Cragars, ARB locker, custom rack, K&N FIPK, 8000lb winch, RE rear LCAs, Optima Yellow Top, RL Rear Bumper, Custom Front Bumper
98 TJ w/5.5" RE Long arm lift, ARB front/rear, 35x12.5, Borla, Warn winch, Teralow, etc., etc..

I may be the transfer case position sensor acting up.

Perhaps. I don't have any external indications of a problem. All 4WD operations work fine. In the description I'm not so sure what they mean by "muxed". It usually means 'multiplexed' so I'm assuming that's what it means here. But Muxed to/with what?

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Matt Townsend
Sebastopol CA

02 Red Libby w/Frankenlift, Full armor incl AllJ stuff, 245 MTRs on Cragars, ARB locker, custom rack, K&N FIPK, 8000lb winch, RE rear LCAs, Optima Yellow Top, RL Rear Bumper, Custom Front Bumper
98 TJ w/5.5" RE Long arm lift, ARB front/rear, 35x12.5, Borla, Warn winch, Teralow, etc., etc..

I think you're right, it probably does mean multiplexed. But that's just a designator for the part, not the problem. It says that it is receiving an invalid state, so it either means something is wrong with the switch/sensor or something is wrong with the controller that is reading it. In either case I say have it looked at. The fact that you also have a malfunctioning temp sensor suggests a problem with the controller, but it's best to have a dealer look at it

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Jeff 2005 Jeep Liberty Renegade
4x4, 6spd, Leather, Sunroof, trak-loc, skids/rails, hitch+shackle, hooks, Alpine/iPod, Thule, GPS, CB, Frankenlifted w/ 31" MTRs
Photos Cardomain

My head's spinning. Saturday I replaced the temp sensor ($35 at NAPA) and now it doesn't throw that code any more. And my temp guage/overheating problem went away.

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Matt Townsend
Sebastopol CA

02 Red Libby w/Frankenlift, Full armor incl AllJ stuff, 245 MTRs on Cragars, ARB locker, custom rack, K&N FIPK, 8000lb winch, RE rear LCAs, Optima Yellow Top, RL Rear Bumper, Custom Front Bumper
98 TJ w/5.5" RE Long arm lift, ARB front/rear, 35x12.5, Borla, Warn winch, Teralow, etc., etc..

So I was having problems with my engine starting. I turn the key and it has a very long turn until it starts like it isn't getting gas like it should. So I changed the fuel filter and it seemed ok that day but the next day same thing. So I read about how to find this code, and I did the key deal and got this po0837 code. Now could this be causing my starting troble or is it just another one to add to the list? It seems like as I turn the key it struggles to start but if I pump the gas it gets it up and running.

Hi Y'all
I though I'd booty some experience.
Problem was No 4WDLo and no Part Time indications. (Other than the position
of the handle).
I cleaned the transfer case position sensor connectors with contact cleaner. No joy.
The connector had 5V (actually 5.14V).
Being an old geek, I got out some resistors & jumped with ~670 Ohms which should
correspond to 4WD Part time. No Joy.
Jumped with ~60 Ohms which should correspond to 4WD Low. No Joy.
Left it unplugged, connected generic (Acton) code reader. No code. Erased anyway.
No Joy.
Decided to try reading the codes with the odometer method. I was never able get
this to work before.
(Everything off. Ignition switch On Off On Off On within 5 seconds.)
It worked. It displayed "P0838", "P0837, "Done".
Plugged in the connector, "4WDLo" & "Part Time" light up again!!! .
Used generic OBDII tool to erase but ignition key still displays the codes on the odometer.
Don't want to disconnect the battery so hopefully they will eventually go away after a few cycles.

Hope this helps someone.

Good luck!