I live in Metro Detroit as well. I regularly pass a silver Jaguar that is parked at a business on the corner of 23 Mile and Ryan (or near there). Is that your car?

 

tps reset needs to be done

 

As an armchair ( total kidney failure productivity issues / mechanic ) , I have to respectfully advise and go with the other work around options otherwise equipment and cost required if even available for TPS orientation

If even needed , but the again armchair

 

Sorry for dropping off the radar, going to get at the ECU here in the next few days.
After getting the measurements on the two Coolant temp sensors, the idle has been much higher, closer to 2000rpm and 1200 at a stop in gear. It is intermittent when it idles this high, but this has got to be a flakey connector or the harness to the connector has a break in the wires. It is really cold outside here which has prevented me from putting in more time after hours at night, but excuses are excuses!

 

Not mine, I’m down in Madison heights/Troy area and work in Novi!

 

A TPS reset is going to be last on the list.
I would like to check every other box before paying someone who may or may not have ever worked on an X300 to touch mine, in poor shape or not.
I’m in an expensive college, and am working too, so getting to work and class is my #1 priority. Getting to spend time with such a lovely vehicle, problems they may be, is a privilege in itself; and am also very lucky to have everyone here contributing their knowledge.
What’s the old saying? “Beats walkin”?
That being said, I have to fix this myself.

This cues me up for the next plan of attack on this problem.
Checking (Again) the continuity of the wires to the sensors, the sensors, and the pins at the ECU.
I will then jostle the cables like its a Toyota, and measure again - because this needs to be as reliable as a Toyota.

Parker7, Hang in there. We need guys in those armchairs to cheer us on!

Oh, I almost forgot.
My driver side high-beam headlight got smashed! I did not see any glass on the ground, so it might have happened on the way into work, but I was still upset and thinking someone might has smashed it. Found a 2000 XJR in a junkyard in my area and grabbed the in-tact set for $60 (Freedom dollars) What I’ve seen is the wiring is really straightforward to swap over. Will make a post about that at another date. Maybe write up a little tutorial with photos if it goes smoothly.

Will do my best to keep this thread up to date on the idle issues!

 

Before removing the headlights , mark the top of the top glass edge as the factory name is up and the lenses chrome rim inboard / outboard positions

You will notice the very small hole for the exiting the car courtesy lamp in only 2 lense assemblies as a guide

This effects how the lenses "fair " into the curves of the sheet metal , ask me how I know , very frustrating going back together if not done

The X308 lenses are 3 palls and the X300 are 4 palls so it takes the large black bracket behind the 4 Lense assemblies

I have my old X300s in the garage to double check

The palls can be frozen into the receiver, and you don't want the palls to break off so penetrating oil spray into the palls receiver a couple of days before

I think the brights on the X300 and X308 are reversed between inboard and outboard positions

Do you have the availability of waterproof splices ? water splashes through the air gaps around the lenses

If not you can seal with bathtub sealastic the standard butt splices , use light bulb grease ( in those small packets at the auto parts store counter ) on the wires before crimping

The armchair is not my jam and doing things to not be , I could write a book , right now blood pressure 200 / 120 dealing with things like going forward , 248 is when I had my stroke in hospital with a side of coma for 2 days waking up with a kidney dialysis tube to my heart to maintain my purity

 

I have over 5,000 posts here. I believe most of them would be about my high idle issues.

I am sorry to tell you.

You need the TPS reset.

No need to be concerned about anyone working on your x300. They're gonna walk up to it, plug in the OBD2 connector, turn the car on (without starting the engine), spend about 3 minutes working the slow computer, and then it'll be done. They'll turn your car off, and unplug the OBD2 device. Then they'll ask you for one hour of labor.

As sure as you are that there is a flakey connection because of the erratic idle, I will reaffirm to you...it needs a TPS reset.

 

Fantastic, Thank you for the instructions! I have cleaned the X308 assemblies (lenses, buckets and brackets - still in one piece from the parts car) but I'll soak the palls now before attempting once the weather warms up above 30 degrees. I will grab some of that dielectric grease for the new connections as well.
Do the X308 headlights have a better/cleaner beam pattern? Sadly, growing up with screens makes seeing at night not the greatest.
That sounds really rough, glad you are here with us and pulling through!

 

I will begrudgingly look for someone in my area for a computer to preform the reset. There is a jaguar dealership somewhat near me that I will call as well.
I am located just outside of Detroit Michigan.
Just to line up the logic in my head:
- The TPS needs a reset no matter what - whether the coolant temperature sensor is okay or not - then once the TPS is reset and lets say the idle is still high, any other changes to the system will go towards improving the idle? Or will tweaking the system bring another imbalance to the ECU, and I am back at square one?
Let me get a new connector for the TPS, mine is a little banged up but still makes a solid connection, and sort out the temperature sensor to get those items off of the list to support a healthy TPS reset.
I think I am thinking about this like having a healthy diet and getting exercise before going to the doctor

 

The reflective silver dish is superior as they upgraded with original manufacture , the glass front is less susceptible to road sand chipping

There are differing opinions on the quality of headlight and amount , Motorcarman ?

Even the chrome rims have a position so mark the tops with tape

In service in the heat of battle might put some heavy general purpose grease in the palls , it will naturally migrate in

The TPS connector as type EV - 1 is used as the trunk dome lights

One hung up kidney stone got both kidneys so now at 3 % , I have a virus in my spine that masked the pain

" Taking a break from the idle issue, sometimes the transmission started acting funny after some spirited driving. I actually don’t remember if this was before or after the idle issues. The transmission control module was switched out for one from a 1996 XJ6L from a buddy’s doner car he had picked up. This, and in combination with several fluid flushes, gear selector slider adjustment meant I had to leave the car before going back to school across the country. It would not downshift unless at a complete stop."

This can be a dirty oiled on the transmission body left without jacking connector , there is a speed sensor in the transmission that goes to the transmission ECU as it crosstalk's with the engine ECU as thay dance together , the connector must first come straight aft ( 1/8 inch ) to unlock and only then twisted 1/2 turn counterclockwise and your off

pic coming with the use of tie wraps someone got a picture of




Is it an observation of downshifting ( solinoids ) ?

The solinoids are about 35 dollars US and commonly avail at the local parts store ( order time )

" gear selector slider "

is that upsairs in the shift lever box or on the transmission body

Point to where it hurts






pic coming

 

Genuine Gear Change Control-automatic (6 Speed Auto Transmission Zf 6hp28,6 Speed Auto Zf 6hp26 Steptronic,automatic) For Jaguar Xj 1995 - 1997 (from 720125 To 812255) (x300) Classic | Jaguar Land Rover Classic Parts

They have this section of the parts cat messed up as the same manufacturer 6 speed transmission

 

Right! The trunk light connector. One of mine is not working anyway so a detached inspection out of the cold is necessary anyways.
From what it felt like at the time, the solenoids did not seem to functioning correctly. On one of the many flushes I did after the aggressive driving (using the J gate as it was intended with moderate acceleration and cornering for no more than 30 seconds which threw the transmission into a fit) there were some distinctive metal shavings on my drain plug. I did not like that, and figured there was some misalignment with what the gear selector is indicating and what is actually being selected - or not selected; maybe it was selecting in-between a gear.
This lead me to the swiper I was talking about connected to the physical J gate selector you move with your hand. I can't find it on the colorful ZF4H image you provided.
I believe I have a picture though...


So this little guy I worked with cafeflyer to make sure visually everything lined up and that all the contacts were rubbing against each other and nothing was loose.
Oh, I do remember tugging on that plug and making sure it was tight and snug, and of course clean. No leaks on this car (beside the power steering rack... problem for another day)
I'm really not sure how beat on this car was before my step-grandfather got it and drove it, then giving it to us once it was on its deathbed needing, well, everything these cars need. I think at this point the transmission since the issue came has had 5 or 6 cycles of draining and refilling.
Old fluid and shavings being dislodged, mixed with the newer slurry, cycling around, and getting stuck in a solenoid?
Sigh*
I will make sure to mark the orientation of the chrome rings!

 

Your pic should be the rotary position switch , this next to the torque converter in your pic

There are elongated holes on the attachment bolts to keep track of before removing

The transmission itself is bullet proof

Do I see a kinked line in the middle of your pic

PS fluid leak , the old hose material ( resivour fittings ( squishes out of shape over the years , cut about 1 inch off and reclanp , the leak makes fluid go everywhere

Your transmission to car linkage should be in the broken into 6 parts on post # 4

Repair Manual - Jaguar Forums - Jaguar Enthusiasts Forum

Bed time for me

 

It's my bedtime too and you give me a 500 page book to study. My next semester of university started early, eh?
I will print out those PDF's at some point for sure. Maybe even get it bound with a hard cover
Thank you for sharing that incredible resource.
I'll give the power steering a looksie, there is cavitation noises as well, but its gone through so much fluid since 2022 that I'm sure its squeaky clean on the inside.

 

Good site for info on swapping the 308 lights
Jaguar XJ6; Jaguar X300; X308 headlights

 

Love that website! Thank you for sharing

 

As you might see from the depths of some of the historical high idle threads, opinions differ regarding the absolute requirement for a TPS reset to solve the high idle issue. After a prolonged period of suffering not unlike your own, fitting a new TPS fixed the problem straight out of the packet. Not inexpensive, but a solution which has continued to perform flawlessly.
My own homespun theory revolves around the tracks of the TPS being most worn around the idle low rpm zone, but other theories are available.
You do absolutely need to reinstate the factory clearance on the throttle blade. Even tiny variations can have a dramatic impact possibly even taking idle outwith a range which the ECU has the ability to normalise when in closed loop.

 

as far as the tps reset goes,
do not worry about spending money as unless you spend all the money to buy a system you can not and will not fix it.
it is a very quick and small job.
with 99% certainty it will fix your issue.
and nothing else you can do will.
you are just wasting your time at this point in my eyes
.

if you are worried about someone working on you car who has never touched one before, if they have never worked on one of these they will not have the equipment or know what they are doing to use it.

 

Gotcha, thank you - I am going to pick up some feeler gauges today. I’m assuming the circular curve of the throttle body and the plate will deform the .002 feeler without binding?