CaptnTim

Hi there! Just happened across this forum...

I've recently acquired a 1999 XJ 4.0 with 180,000 miles for basically nothing. I'm a diesel truck guy and marine mechanic and really have no experience with Jeeps, but have a good general knowledge base and all the typical shop skills you'd expect.

I suspect this vehicle has not seen outstanding regular maintenance and there are a couple issues. I've got 02 sensor codes as follows:

P0135, O2 sensor heater circuit malfunction bank1 sensor1

P0141, O2 sensor heater circuit malfunction bank 1 sensor 2

P0138, O2 sensor circuit high volts bank1 sensor2

It runs pretty terrible when cold...stalling, rough idle...which explains the O2 sensor heater malfunction codes. I'll replace the sensors, check the wiring & fuses, etc. I've also done a basic tune-up with plugs, cap & rotor, filters, oil, fuel injector cleaner, etc.

As a general rule, I've been staying away from Bosch O2 sensors...does this apply here? Any brand suggestions? RockAuto has some good prices, but I'm open to suggestions.

Thanks in advance for any comments & suggestions...

Tim

EMAXX620

almost everything i read about jeeps and o2 sensors says stay away from bosch. I replaced my precat one with a NTK (same manufacturer as NGK spark plugs) It came with antisieze already on it

if you want to go with the same brand, go to the NTK site, plug in your jeep info and then get the product number and find it on rockauto.

good luck!

CaptnTim

Thanks for the reply. I've spent the past hour reading search results and all sorts of helpful information. There does seem to be a general consensus that NTK makes the MOPAR O2 sensors, but some people seem to still insist that you must spend twice the money for a MOPAR part number.

Have you had any problems with the NTK's? How long/miles have you had them in there?

I'm tempted to do what you say and just get the NTK's from Rock Auto.

Thanks again!

lesagesix

I would go with with the NTK's from Rock Auto. I ordered a clutch slave and master cylinder set up from them, and was able to get it fast. Not to mention how knowledgeable they were. Also the price, wow. Mopar $270 + Rock Auto $112.

nomeaculpa

Crap. Just replaced both O2 sensors with Bosch, as well as the shift solenoid. Drive 50 miles, check engine light goes out...then 5 miles later it comes back on.

Haven't been down to have diagnostics run again, just yet, but I KNOW it's one of those damn sensors.

Is it quality control with Bosch, or do they just not work well with Jeeps?

CaptnTim

From what I'm reading, they don't work well with Jeeps....especially the 4.0 I6. No one seems to be able to explain this, but that's what I'm reading. I can tell you from personal experience that many of the big aftermarket parts names you get off the shelf are NOT the quality you'd expect.

Random example: In my 1 ton Dodge/Cummins I put MOOG ball joints in and they were shot in 10K miles. A little research found that everyone was having the same problem with MOOG chassis parts.

This also not this first time I've heard this experience with Bosch O2 sensors, but no one seems to be able to explain it.

Good luck...

EMAXX620

im guessing the bosch sensors are just made with different components inside the sensors which may be more sensitive and give the computer a false reading. Ive only had the ntk sensor in place for maybe 3-500 miles. i DO have a check engine light, but its for my rear sensor and i dont care to replace it because the post cat sensor doesnt deal with air fuel mixtures or anything, its just there to tell you if the cat is functioning or not, no reason to change unless the light bothers you.

mpars

I replaced my o2 sensors with bosch as well. For about 2 months it was fine....now my check engine pops up then goes away and pops and goes away telling me its both o2 sensors. i think they have a lifetime warranty so I'll probably just exchange them. Do they have that NTK brand at oreilys or autozone?

UserID6095

I put the Bosch o2's in mine before I knew better. No CEL or any random issues, so got my fingers crossed. If they do fail or throw a CEL I will be replacing with the NTK's as well.

Cpt' for the DTC's, you are on the right path. Check wires, ASD relay, the fuses and of course the sensor. I read that you can unplug the front o2 and drive it around. If your fueling issue goes away then you know where the problem is. The rear o2 on these is only in place to monitor the cat convertor and has no role in fuel/air ratio. Hope this helps.

plotski999

I replaced both sensors in mine with Bosch as well, this is the first I've heard of them being bad. I've had them for about 10 months now with no problems so I'll just hope I don't run into any problems at this point.

CaptnTim

Thanks for the replies everyone, I ordered two NTK sensors from Rock Auto both for $88 which was $50 less than the MOPAR part numbers. Great forum here...I'll be back as I continue to tinker with this little project.

One last thing....I also have to do front axle joints. Is the little Dana 30 a C-clip axle, so I assume I'll have to pull the diff cover to slide the axle shafts out? It's been a long time since I've messed with axles this small (read: anything that's not a full float).

Thanks again for all the replies!

Tim

EMAXX620

If your talking about the U-Joints, you dont have to unless they had c-clips on certain years. I know on my 2000 i just pulled the shafts out when i had to replace my ujoints. Just be careful when you put them back in so you dont damage the seal inside the tube.