Some codes will not trigger unless the fault occurs on two successive trips. I think the DTC Summaries manuals indicate which codes fall into that category. Also, there are situations where a system is not operating within specification to the extent that the readiness monitor will not reset, but not to the extent that a code will be set. That's where an experienced mechanic can be helpful, monitoring Live Data for O2S signals, fuel trims, etc., and perhaps conducting other tests as relevant.

 

My apps can live view a number of monitors (see attached image) which ones should I monitor, and what am I looking to see with them. I don't think the apps can log the data, only live view so I'm not sure if I'll be able to post any of that data here.

 

You'll basically be staring at any/all to see if anything's not plausible.

You know there's a fault so any clues will save what we used to do in the old days - parts swapping in hope.

 

I recall reading a jaguar training manual which I believe stated which codes were blanked out when you had certain other codes. I will look and post if I find it

 

HERE IT IS!

 

lets see if the whole document will load
lots of good stuff here

 

It doesn't apply to his MY car.

However. it shows the kinds of things that may be going on.

Earlier versions are on the site as free downloads and if anything will be more likely to apply.

 

I uploaded some of the earlier versions in Post #18. Unfortunately, the OBD manuals published during the AJ26/AJ27 era are not as complete or informative as the later versions, so some intuition and interpolation is required.

Cheers,

Don

 

Well I don't know what would be not plausible in that all that data. I wouldn't know what would be normal for o2 voltage or fuel trim level.

 

That's where an experienced and knowledgeable mechanic may be able to save you a lot of time and frustration.

 

Mechanic is not in the budget at this point, but I do have a good bit of time and this car has proved to be and endless source of frustration!

 

It's virtually impossible for others to diagnose the malfunctions remotely, so try posting in the U.S. Western Regional forum to see if there is a knowledgeable member of the forums in the L.A. area who may be willing and able to help:

Jaguar Forums U.S. Western Region

Cheers,

Don

 

So since my last post the car has pretty much been sitting in my driveway, I've started and driven it a few times to keep the battery charged but mostly its been collecting dust. Today I took the car to my Jag mechanic. He basically told me that all he could do is preform the same drive cycles I've been doing and that without a DTC to point towards a problem there isn't really a way to diagnose if anything is wrong. The only suggestion he had was to do a hard reset to start from zero and see if it trips a code. So I did just that. I unplugged the negative terminal left touched it to the positive for about a min. Hooked the battery back up and went to check the monitors to confirm they had been reset. I turned on the ignition, but didn't start the engine and scanned the monitors. They were exactly as they were before, with the o2, egr and component failed but everything else saying pass. I figured I hadn't held the negative terminal to the positive long enough or something and it must not have reset, so I unhooked the battery and tried again. I left the negative terminal sitting on the positive and then turned the ignition on and stood on the brake pedal for a full min, then I walked away leaving the negative terminal on the positive for another 5 min. After hooking it back up I scanned it again with the ignition on but the engine not running and got the same thing. The same three monitors not passed, the others passed.



How could any of the other monitors be passing if the car hasn't been driven and the engine hasn't even been running?
Out of curiosity I also did a scan for DTCs, popped up with p1646, for bank 1 O2 sesnor, this is again before the engine has even been turned over. How could it instantly have a code with zero miles of driving? Started the car to see if the CEL was one, it wasn't. Drove it around to the store and back, about 10 miles of city driving and scanned things again. DTC is still there but no CEL and the monitors are still the same.

I'm somewhat optimistic because the code point my in some direction but I'm also left more confused. How can a DTC pop up instantly with zero miles of driving and the engine not even having been started? How can I have any monitors already passing after a reset and the engine not even started? How can I have a DTC and not a CEL?

I guess I'm going to drive it around a bit more and see if the CEL come on and go from there.

 

Hi OUScooby,

Please edit your signature to add the year, model and engine details so they show up in all of your posts. I had to scroll all the way back to your very first post to be reminded of this info, and most members don't have time to bother.

On the X308 it may be that while you have the battery cables touching, you need to turn the key to position II (Ignition ON) for the hard reset to work. I can't recall, but obviously your keep-alive memory capacitors are not all being drained of their charges.

P1646 represents a problem with the O2S circuit and according to the DTC Summaries, it can be triggered after 8 seconds of the ignition being turned on. That is a pretty good clue that there is a problem with your Bank A upstream O2S or its circuit. The manual indicates that this is a two-trip DTC.

Cheers,

Don

 

I did have the ignition in the on position, still I guess it did not do a reset. I cleared the DTC and that got the monitors to reset. I'll see if that code comes back and see if I can't get those monitors to pass by trying the drive cycles again.