Jeep TJ disappearing coolant
- Thread starter sergioemz
- Start date
Hello! I just had my 0331 OEM head replaced with a brand new clearwater head. disappearing coolant issue is finally solved but now after driving about 20 miles with the new head the engine light came on with the P0161 code (bank 2 sensor 2). (I find hard to believe the sensor went bad at the exact time the head was replaced) I cleared the code but the engine light came back again after 40 miles drive.
P0158 code (high voltage) also came up the first time, it hasn't come back since then.
While looking at the OBDII live data I see the voltage in B2S2 is 1v when the motor is idle, while driving, the voltage fluctuates between 0.2v and 0.9v, some times going up to 1.2v for a couple seconds.
Any suggestion on what to check next?
P0158 code (high voltage) also came up the first time, it hasn't come back since then.
While looking at the OBDII live data I see the voltage in B2S2 is 1v when the motor is idle, while driving, the voltage fluctuates between 0.2v and 0.9v, some times going up to 1.2v for a couple seconds.
Any suggestion on what to check next?
P0161 is a code for the O2 heater circuit. Check the wiring. Pull up the FSM for your Jeep under Resources for troubleshooting the code.
Also check the fuse for the heated O2 sensors. Any time you have work done there is the possibility of something getting disturbed, make sure the wires going to the O2 sensors are not pinched, melted or cut. There are actually 2 circuits going to the heated O2 sensors, a 5 volt reference circuit to the ECM for communication and you already proved that is good by seeing voltage readings (they will vary depending on O2 content) and a 12 volt circuit for the heaters which comes from the vehicle 12 volt system when the ignition is powered on, which is where your problem is. Don't blame the sensors. The voltage you are seeing is in the communication circuit, the OBD won't report voltage on the heater circuit, only that there is none.
Thank you all, I decided to replace it with the NTK #23141. cleared the code and it hasn't come back. also the voltage isn't stuck anymore at 1V when the engine is cold. 
Thank you all, I decided to replace it with the NTK #23141. cleared the code and it hasn't come back. also the voltage isn't stuck anymore at 1V when the engine is cold.
Mine went bad right after after the transmission was changed. I replaced the b2s2 sensor and it went bad about a week later.
The insulation was stripped/stretched at the plug where the b2s2 connects, causing it to be shorted out. The plug was captive between the tub and transmission, so I cut the wires from the harness and added a long splice.
Mentioning this in case b2s2 issues come back.
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Does anyone know if I can pull out the head bolt #11 (the one in contact with the coolant) to put sealant on it without messing up the whole head torque? I have a small coolant leak because the mechanic missed the sealant when changing the head
I wanted to do it myself to make sure it’s done properly as i don’t trust the guy anymore. It shouldn’t be difficult, but if there’s a chance of messing with the head torque I rather leave it as it is because the spill is just a few drops every once in a while.
No, it’s leaking through manifold bolt #1 which is perpendicular to head bolt #11. In this clearwater head, there is no wall between those two holes.
I would remove it and put the correct sealer on it then re-install. I don't think you'll mess up the torque, that one gets 10 lbs less than the rest anyway. Pretty sure when the coolant is under pressure it can work it's way up the head bolt and come out on top of the head and contaminate your oil.
Thanks, yes, i’ll do that. The top of that bolt is outside the valve cover so if it reaches the top it would fall outside the head, I think I’m safe there. Thanks for the advise.
Didn't even notice that, not so critical then, but a nuisance for sure. Are you in Sonora?
I’m in Jalisco, Guadalajara
Nice! My son has a place on the beach in Puerto Lobos, Sonora. The fishing is good....
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