My car seems to have a problem passing California emissions. The spark plugs were new when I bought the car and also replaced the front catalytic converters, O2 sensors, and all the ignition coils. It's been tested a few times but each time it has failed with the same high readings (HydroCarbons and Carbon Monoxide)

The car seems to run perfectly fine, as in idle and power range throughout RPM's

 

They do a sniff test on OBD2 cars?

 

I always thought they did unless the car was 4 years old or newer?

 

Same problem with my '97 x300. Failed California smog a few days ago with high readings and all of the monitors could not be checked as they did not reset. Before this I had replaced all 4 o2 sensors but the o2s codes reappeared during the smog check. As this vehicle had new cats installed earlier this year by the previous owner ("Walker Cal-Cat 81651") my mechanics conclusion was that I must have a faulty ECM. I bought one online and tried it today. I drove it about 10 miles and then checked for codes. It completed the drive cycles and tested all the monitors - all good except for the cats. Now it shows the codes 0430 and 0420 which are for the catalytic converters. Are my cats faulty? Where do I go from here? Any help is greatly appreciated.

 

If you replaced the ecu and did not do a lambda sensor "reorientation, there is a pretty good chance you have incorrectly connected lambda sensors. Check the archive. As hard as it may be to fathom what was going throught the engineer's head, there is no hard rule as to whether the A or B bank sensors are connected to a particular connector. that relationship is set in the ecu via configuration.

 

I checked the archive. For sensor orientation you need a WDS tool which means going to the dealership. I was hoping to find a solution that doesn't involve bringing the car to the dealership . . .

 

Hmm I haven't tried replacing a fault ECU that maybe my next step.

 

There's no need for this orientation with just a single O2 sensor replacement, is there?

 

Just tried to switch the engine ECU's from a 97 xj6L with my 96 xj6 base but they weren't compatible.

I'm not sure if it was because of the 97 being longer wheelbase or my specific ECU only compatible with 95/96 models as I've seen for some ECU's listed online.

Does anyone know how to tell which ones would be compatible with my 96 XJ6?
I've found one locally pulled from a 1995 XJ6 but the part number for the ECU is LNA1410AH as where mine is LNA1410VF/101

 

See the thread called "ECU Compatibility".

 

I replaced the ECU and seems to run fine and a lower but smoother idle (650rpm but I'm not sure what it should be, I think with the previous ECU it was at 750/800rpms on idle).
I did get codes P0138 and P0158 which point to the O2 sensors.

Are the codes just showing up because of the new ECU and needs time adjusting or does it actually see that there is something wrong with the O2 sensors?

 

I have a 97 x300 which failed smog last week. I changed the ECU a few days ago and now I have the same 2 codes P0138 and P0158. I had replaced these sensors only a few weeks ago. I believe that going to the Jag dealership for orientation is the next step. According to 'sparkenzap'

"If you replaced the ecu and did not do a lambda sensor "reorientation, there is a pretty good chance you have incorrectly connected lambda sensors."

Please post if you resolve this issue. I'm taking mine to the dealer next week. I'll post here after.

 

This TSB has the info for performing the O2 orientation setup (see page 13).
You might try to swap the PROMS from your original ECM.
Throttle adaptation might be needed.

Lots of us have WDS with Jaguar software so you might find someone and save a trip to the dealer.

bob gauff

 

Thanks Bob, I have a few questions for you which I hope don't seem too stupid.

1. Why try swap the proms from the original ECM?
2. How would I know if throttle adaption is needed?
3. How could I get WDS software from someone and is it difficult to use it?

I checked the TSB link and the info that it has regarding the o2 orientation is this:

"Using the WDS, perform the oxygen sensors orientation test. (Select set-up
and configuration, engine and transmission, oxygen sensor orientation.)"

Sounds easy - if you know what you are doing - which I don't . . . yet!

 

Seems that I have figured out my problem. The two O2 sensors in the rear.

First I tried to swap the ECU's from a 95 but the part numbers did not match but everything seemed to run ok except for some slight hesitation accelerating and a very slight misfire around 75mph and 2500rpm which caused the car to shake on the freeway. My ultragauge monitor came in yesterday and I was able to monitor the O2 sensor voltages realtime but the rear ones were getting voltages that weren't normal (between .2 and .7 when it should be outside those numbers) and also the short rate fuel trim as well as long term for each bank and I was getting numbers that were way off (-25%/24%) when the short term should only be around -/+5% all around.

I switched out the rear O2 sensors from a 97 xj6L and I was able to get the voltages correct which pointed my problem to the o2 sensors and thinking that the 95 xj6 ecu was not compatible with my 96 although I was getting better gas mileage with the 95 ecu (17/18mph compared to the constant 15mpg with the original ecu) but I did switch the ECU's out again to the original with properly functioning O2 sensors and now everything runs perfect. No hesitation/misfire and correct voltage readings for all four sensors as well as close to normal fuel trim readings.

 

I'm glad you sorted it out. Your post got me to check up on my rear o2 sensors. I called the mechanic that supposedly changed them out and guess what? He didn't change the rear o2 sensors, just the front. I had a look(took me an hour to find them), and the rear o2s are covered in oil. I had a leaky valve cover gasket that I changed out a couple of weeks ago which appears to have been the source of the oil getting in the sensors. So changing those could well solve my problem too. Seems a bit of a pain to remove rear o2s and connectors. My hands don't fit where the wires go! Did you splice and connect or totally replace sensor and connector?

 

The rear O2 sensors are a little tough to get to. The left one is a little bit easier and it only took an open ended box wrench to take off. The right top one was the hard part. I had to use a wrench head that connected to a ratchet with an extension long enough to go from the bottom of the exhaust to the O2 sensor.

Let me know if that makes sense to you and if not I'll show you the exact tool I used.

Also the cable guides for the O2 wires, the one connected to the engine/transmission, I just got off, I didn't bother taking off the star bolt.

 

Got the o2 sensors in but shes not running as smooth as before. I think I will put the original ecu back in. Did you try a pre-smog yet to see will it pass? Hope it does for you.

 

Yes, try putting the original ecu back in. That's what I did. I did do a pretest and HC and CO levels are within passing levels but the NOx levels are still a little high but I'm thinking it's only because I only drove it around 90 miles after putting in the new o2 sensors. I added some lucas fuel cleaner that is supposed to lower NOx levels so after this full tank I'm going to take it back to get tested.

 

I put the original ecu back in and it is running worse. It seems to be lacking power and the car vibrates when I go above 40.