Hello diagnostic super sleuths!
Ive been working on my ‘02 Sport and it’s running beautifully after warm up. (A bit of idle fluctuation when cold but then settles down to a steady idle in the low 700rpm)
Ive recently had the intake manifold off and replaced spark plugs, coils and injectors, plenum gaskets top and bottom, elbow breather, IMT o rings. Also changed both o2 downstream sensors after seeing 0.00 volt output readings on the original OEM sensors.
I currently have codes p1383, p1584 and p1788 as well as an amber warning gearbox fault and engine fail safe mode as well as flashing DTC light - but despite all that the car runs and drives very nicely.
At present I’m clocking very high negative LTFT -25% at idle and -14% at 2500rpm.
Is anyone able to make sense of theses symptoms? What should I be looking at to bring down the rich fuel mix?
Thanks in advance for any clues.
cheers,
Ben

 

Flashing MIL = serious catalyst damage occurring

Don't let it keep happening or the cost will be awful.

It's possible they're already bad and affecting trims

 

Thanks for the warning @JagV8
I don’t actually have a check engine light illuminated - apart from other warnings mentioned above. The DTC light is flashing though. 🤔
Any advice on what’s might be causing the high negative LTFT? Or any other red flags seen in the diagnostics?
thanks heaps!

 

Some big questions:

You mentioned a slew of recent work, such as new plugs, coils, injectors, etc. Routine maintenance? Money to burn? Was this in response to a particular fault? If so, did the symptoms change after the work? It's important to know whether or not we are dealing with new problems that may have started after other recent work.

Did you ever do anything with the same throttle body fault (P1584) seen in your previous thread?:

https://www.jaguarforums.com/forum/s...rts-up-243974/

The advice given then is still valid. I didn't see any updates since that thread petered out and died. (Hint, hint, go back and update it... ) For that code, you are probably looking at having to replace the throttle body assembly. Don't panic, you can either have your existing unit repaired or try a used one. For a Hail Mary, carefully inspect the electrical connectors at the throttle body, but don't get your hopes too high. P1584 generally refers to an internal fault. See the links given in post #8 in that thread. One forum member resolved a code P1584 by having his throttle body rebuilt. My $75 gamble on a used unit paid off, and has been working fine since 2015.


For code P1383:

This is fairly common with the early V6 engines. I've had P1383 (and P1388 for the other bank) several times on my '02 V6 (approx 350k miles).

Two theories, both related to oil viscosity and how it affects VVT operation. Some have reported good results switching to a thinner viscosity. With higher mileage, thicker viscosity seems to work better. This thread should explain what you need to know:

https://www.jaguarforums.com/forum/s...bad-vvt-68687/

FWIW, I run fairly thick 10W-40 in my car. When I put off an oil change for too long, the viscosity tends to break down and the first sign is one of these codes. A fresh oil change has always taken care of it for me. If unsure whether you should try thinner or thicker oil, don't worry too much. It's not a permanent decision. Try one or the other and see what happens. But if dealing with a high mileage engine, thicker seems to work better.

With that said, I don't think a VVT issue by itself will cause much trouble, other than setting a code. The few times I've seen it there were no other symptoms or changes in performance that I could discern.

P1788:

Not sure what to suggest for this one. It's a transmission fault, saying one of the shift solenoids is misbehaving. I had a similar code on my '02, and it was resolved by replacing the solenoid shift pack. Not a lot of fun, as it was messy working under the transmission, but not overly difficult. Not very expensive, either. But others have mentioned certain transmission faults can be erroneously flagged by engine fluctuations, so maybe hold off of on this one until you get the engine fully sorted out.

I am thoroughly perplexed how you are getting a flashing Check Engine Light all by itself. From what I understand, this light only flashes in conjunction with a misfire judged severe enough to overheat the cats ($$$). You should have a corresponding misfire code (P0300-P0308) any time the light flashes.

One thing I did notice with your scanner screenshots is the Intake Air Temperature (IAT) was very high, 64C in one instance. Yikes! That's toasty. Had the engine just been started after being heat-soaked on a hot day? I'm not sure how quickly the sensor responds, but I'd think after a couple of minutes max it should be much closer to ambient with fresh air flowing through the intake. Unless it really was 64C that day...

 

*I meant flashing DSC, not flashing DTC in post above! I got my acronyms mixed up. Sorry for the confusion!

Thanks for the very detailed assessment of my DTC’s @kr98664.
I changed the spark plugs, coils and injectors as a decision to start fresh and considering I was going deep to do the elbow - it was done for convenience really. When I got the car, 2 months ago, it had been sitting for 2 years and last previous work was done in 2014.
After doing that work the car improved dramatically and the idle hunting went away - thinking maybe it had fixed itself. It has returned but to a much lesser extent.

Re 1584 code - Ive recently gone ahead and bought a used TB (40£) from the UK and am just waiting on its arrival to Australia- taking a punt that it’s internal circuit is functioning properly and that it may solve that problem. Your positive experience doing that gives me hope!

I've read a lot about the 1383 code and will try the 1 quart ATF with engine oil when I change again soon. Good to know that one isn’t a serious concern but something to keep an eye on. My cars done 180k kilometres.

Regarding the 1788 pressure control solenoid - I’ve watched a lot of videos on changing the solenoid pack and I feel I know the 5r55n intimately haha. Can I ask - would you suggest just changing the ATF and filter first to see if that makes improvements on the shift from 1st to 2nd? At the moment the shift is fine under light load, although there is a little punch shift when under acceleration. Or should I just change the solenoid pack whilst doing the filter and fluid? I see solenoid packs are pretty cheap on eBay. The servo bore wearing condition on these transmissions is another possible area of concern.

The air intake temp you noticed is quite high and the car had been idling for about 15mins whilst I was doing diagnostics. I’m wondering if my cooling fan isn’t coming on, although the temp gauge sits on halfway and the temp usually reads about 96-99 degrees. It does seem a bit hot though. I’ll look into what’s going on there.

Do you think my reconditioned fuel injectors could be delivering too much fuel and hence my rich condition?

thanks very much for the input.
cheers

 

I had on my 05 3.0 the same richness you seem to have. All I did was to clean the MAF and have not seen it in the last 80,000 miles. I do not know if the IAT on your engine is integrated to the MAF. It may just be a faulty MAF and for your car they are not expensive.

Tom in Dallas/Plano
2005 S-Type 3.0 119k

 

Okay, things are starting to make more sense. I'm not sure what would be causing the flashing DSC light. Perhaps when the engine is in failsafe mode, this also inhibits the DSC system? Just a guess, I don't really know. If fixing the P1584 code doesn't also clear the DSC fault, you may have to invest in a scanner that can read those codes. The basic OBD II scanner won't retrieve those codes, so you'd be working blind without the details.

I'd say the P1584 is your top priority. It was a piece of cake to swap the throttle body, maybe an hour or so. Access was a little tight to the hoses underneath, so I undid the far ends and removed the hoses still attached to the TB, then swapped them over to the replacement unit. Way easier than trying to do it in situ. Don't forget to order a new gasket where the TB attaches. I'm more than willing to gamble your money on a used TB. Worked for me.

​​​​​​​
This was my experience replacing the solenoid pack:

https://www.jaguarforums.com/forum/s...-p0745-205599/

I'm always hesitant to suggest doing a bunch of work in one fell swoop, in case you inadvertently introduce a new fault. But in this case, it wasn't much fun dropping the pan, refilling, etc. No matter how careful you are, it's messy. Mind you the overall job wasn't ​​​difficult, but the logistics were tricky to jack the car up high enough and then put it on jackstands, and most importantly of all, keeping it level to refill the fluid. Super easy in a shop with a hoist, but no so much working in the driveway. One tough part is the jack points in the rear are the only places you can also install jack stands. There's precious little room to put a jackstand next to the jack. So in my overinflated opinion, if I were considering replacing the solenoid pack, I'd do it at the same time as the filter and fluid.

I would still suggest taking care of the P1584 first, just in case the transmission issue is an erroneous fault triggered by the engine operating in failsafe mode.

If you do need to replace the solenoid pack, make sure you read my travails at the link above. You will need a ratcheting 10mm wrench, as there is not room for a socket. You will also need a set of long Torx bits, something like this:


Those are security bits, but they will work on regular Torx heads, too.

This is the solenoid pack I installed three years ago, no issues since then. I do not know if they will ship internationally, but maybe you can find something closer:

https://www.ebay.com/itm/5r55n-Solen...2z4000b4500004


The 5R55N transmission is a garden variety Ford unit, with millions sold worldwide. Don't scare yourself that it's some exotic unit. You should have no trouble getting parts for it.


I watched my car on a short drive this morning. Ambient temperature was about 60F, and the IAT value showed 97F after about a 15 minute drive to breakfast. (I had buttermilk pancakes and eggs, grandson had French toast.) I do not know if my IAT is also reading high, or if the intake air is really affected that much by underhood heat. Perhaps what I noticed doesn't really matter. I don't know.
​​​​​​​
That's not unreasonable. I'd still take care of the P1584 first and see what happens.

Do you still have the old injectors? IIRC, access to replace them is a pain, but it might be worth trying down the road.
​​​​​​​

 

Take a look at this thread;

https://www.jaguarforums.com/forum/s...solved-196723/

 

Gday Tom,
thanks for that - yeah I’ll clean my MAF and look to replace it as a precaution. I’ve just ordered a Chinese one ($20) and I’ll see if that does anything or not.
Good to know that worked for you.
cheers mate 👍

 

We have our fingers crossed for you, Stoic, as these forums are literally littered with the bad experiences of folks who introduced cheap Chinese components into their engine management systems. Original, or OEM for these parts, IMHO.

 

I would have ordered from Rock, there are several for under $45 and may be much more reliable. The test is to put the new MAF in, clear the adaptions and then just let the car idle for 15 minutes. If the MAF is not exactly right, then it will throw a code.


TBB

 

Thanks for the input on this thread.
I will post an update on progress after I replace the TB with the used one and the knock off MAF sensor.
I’m also going to clean the original fuel injectors and put them back on, because I think the increased rich condition could be related to the recon replacement ones which came from the US and may have been for a Lincoln LS or other Ford.
Then I’ll tackle the solenoid pack replacement job and a tranny fluid and filter refresh to see if I can make the p1788 go away.

cheers all!
Ben

 

Whoa... Are you now telling us that you "may" have installed incorrect injectors on the engine...? Also, I would recommend that any parts swaps done are on a "one at a time" basis. If you throw a bunch of new/used parts at the car all at once, you will have no idea which part improved or worsened your situation...

 

Hi StoicJag,

I noticed that you are using the iCarsoft LR v1.0 reader. Are you happy with it?
I’m looking for a suitable reader for my MY2000 S-type V6 and my MY1997 XK8.
Thanks!

 

The reader will work fine on both your cars and allow you to see much more in live data and to look at all th modules that generic readers will not. Of course the best you can do is to get a version of the SDD which when used with your model cars will revert to the IDS and then you can apply firmware updates to the TCM and ECU, if there are any. Also would allow for clearing TCM adaptions and see many more things electronically in the CAN.




https://www.ebay.com/itm/19230422649...gAAOSwgslbAgQf

https://www.obdii365.com/wholesale/j...-mongoose.html



Tom in Dallas/Plano

 

I’d be focused on the O2 sensors. You should not be getting zero voltage. And for some reason It can’t calculate the short term fuel trim on one side. You need to watch the voltage and current on the O2 sensors and make sure they move above and below zero repeatedly. You shouldn’t have a constant output

 

But he was showing O2 voltage at idle. I can't be sure about the voltage at 2500. He would need to run it again and see if the same thing happens. I also would suggest he run live data while driving normally and see what he (if he can) record on the voltage.

TBB

 

My idle fluctuating problem (P1584) has been solved by changing the throttle body for a used one sourced from the UK and sent to me in Australia. So stoked and it just idles like a dream! This code has now gone away.
The working throttle body also has made my ‘engine fail safe mode’ warning go away.

The rich condition has also been solved by deciding to thoroughly clean and refit the original fuel injectors. My hunch was that the ones I bought from Amazon (identical in appearance to the OEM injectors) might have been delivering too much fuel each pulse and my ECU was struggling to trim it back to achieve the stoichiometric ideal. The original injectors are working well and LTFT are back to close to zero.

Whilst changing the injectors I had also discovered that the lower intake manifold bakelite piece had a cracked and broken fastener causing it not to bolted down correctly. I sourced a replacement piece from a wrecker and bolted it on and the smell of engine oil in the car has now gone away.

Regarding my O2 sensors readings - I replaced both sensor 2 (downstream) and one of them still has a zero voltage reading which I will have to look into the reason why? Do these sensors feed data to the computer regarding fuel trim or do they just monitor whether the cats are working properly? I’ve heard conflicting info about what the lower sensors do?

On last scan my P1383 VVT code has gone away and I’ll keep an eye on that.

Ive still got the flashing DSC light and I’m thinking it’s one of the front wheel speed sensors as both rear ones appeared to be clean. Not sure what else it could be? I did notice on my iCarsoft reader that all four wheel sensors were in sync regarding wheel speed when I went for a drive whilst checking it? So maybe they are working fine? Is it true that a Jag specialist can stop that light from flashing?

Still got the pressure control solenoid P1788 code and I’m currently trying to figure out if I’ve got a wiring problem or that solenoid is starting to fail. I noticed on my live data scan that it has a lower current compared to the other two solenoids. See attached pic. Does that suggest anything to anyone?

Thanks for all the help and I’m making good progress thanks to the Jag hive mind. 👍🤗🙏


Pressure control solenoid current

 

Hi@Porterve -sorry for the delay - yeah I’m happy with this reader. It gives 118 live data points on the power train module and delivers enough bang for the small amount of bucks to analyse your car. Mine cost me $140 AUD. Well worth it. 👍

 

Hi Tom,

thanks for your suggestion.

I notice from the links you posted that the s/w ver 1.60 which is included with the Mangoose cable only supports vehicles from 2005 up.

Do you know which version s/w supports my 1997 XK8 & 2000 S-type?

Many thanks.