i plugged in my superchip and used the diagnostics function. it gave me these 3 codes:
1.P0141: o2 sensor 1/2 heater performance
2.P0705: transmission range sensor circuit
3.P1694: no engine bus messages

what do they mean, how serious are they, and what can/should i do about them?

99xj with 97 motor. 4.5" lift, 31" tires, cold air intake, cat-back exhaust, superchip

 

Well, I'm just learning here, have a few ideas tho.

I believe there is a relay, and maybe even a fuse for the 02 sensor heater. Also check the wires to them. There's wires both to the rear one that monitors the cat, and the one down on the exhaust manifold.

The range sensor is the NSS I hear. (reverse lights work? Starts, starting OK? Shifts OK?). I wonder though if the sensor on the T-Case might do that.

 

you're right about the reverse lights, and some days it starts a little rough. but it shifts great. do you think it would be worthwhile to replace all the o2 sensors? i have no idea what that would cost. and this jeep is a bit of a restore/rebuild as i swamped it really bad in may

 

Here's a deal on the NSS:
http://bc4x4.com/tech/2010/jeep-neut...ty-switch-nss/
As far as starting, it will make it to nothing at all, jiggling the shifter is the usual remedy.

As the front O2 sensor ages it might cause you to run more rich. Just for economy it might be good to know it's good. Your code is just for the heater. I believe it actually uses some current is why it has it's own relay and people mention problems with the wires. I'd look to see if they are not burnt by the exhaust, maybe unplug the connectors. All Jeep connectors can be sprayed out with contact cleaner and reassembled with dielectric grease. Anywhere you can, tighten the clips with a dental tool or pick.

I googled that "no Bus". Our old friend the CPS was mentioned.

 

Does the engine run with the NOBUS message, or does it not run? Important distinction here.

I agree with DFlintstone. Whenever you have a code for an oxygen sensor that mentions the word HEATER, the fuse for that circuit must be verified. Failure to do that has resulted in many people going on a goose chase. It is not uncommon to have an issue with that fuse.

The fuse is located inside of the power distribution center (black box) under the hood on the passenger side. I can't recall the exact location but it is in the 13-17 range if memory serves me. It is a 15 amp mini fuse.

Plenty of time to replace the sensor, etc. if the fuse checks out.

 

the only time it ever showed the no bus message was when i plugged in my super chip, it said it where the kms are

 

Here's a pic of the O2S heater fuse location for the '98/'99 XJ.

 

thanks everyone

 

Much thanks again TJ, and CCken, man, that photo ROCKS!