1999 xk8....
replaced throttle position sensor and now it throws engine fault code/stability fault code. How to reset?? Old tps sensor was falling apart and car ran good before as long as the tpa was taped together. Has anyone ever fixed or solved this?

 

Is this all part of the same set of issues you posted in this thread?
https://www.jaguarforums.com/forum/x...trical-240791/

1. did you mark the relative positions of the old sensor and throttle body to ensure the new one went in exactly the same orientation?
2. actual codes?

Graham

 

These cars do NOT like electrical changes with the battery still connected and without doing a "hard reset" of the cars computers and electrical systems between changes. To do this (and this is what I do sometimes) remove key from ignition. Disconnect the NEG battery cable. Return key to ignition and turn to position 3 or run. Return to trunk. Hold or clip the NEG battery cable (still attached to car body) to the POS battery terminal (still connected to the POS battery post) for several minutes.

You need to get the new position sensor to the exact or as close to exact position as old. Bolt/tighten down.

If it's designed like the 2002 sensor,,,?

If you look closely at the old sensor with a light you might (if your lucky) be able to find something of witness marks on the "swivel" where the bolts on the old throttle PS used to be. Work with that. Align the new with the old as best as possible. Button it up

After a while reconnect battery and start the car. Don't touch anything and let the car do it's thing. Don't touch the gas peddle. It should search a bit for it's new normal. Wait til at full operating temp. I wouldn't hurt to let it cool and do this process again.

Other folks will jump in and correct my mistakes.
Good luck

 

Welcome to the Forum; you'll get lots of great advice here and get to know some awesome members.

Here's the procedure I use for a hard reset:

Jaguar Hard Reset
Ignition Off
Remove and short Negative connector to Positive for 30 seconds. Replace and tighten negative post to battery.
Turn ignition on but don't start.
Reset windows.

Then:
With ignition switch in Position II, (not started), slowly press accel pedal through kickdown detent all the way to the floor; hold 5 seconds. Release pedal and repeat one more time.

Then: Start engine, idle until normal operating temp is reached. Switch off.

Then: Restart, idle for 2 minutes.

Then: Apply foot brake, shift to drive, idle for 2 min.

Then, drive for 5 miles of varied conditions.

Finally, reset audio, seat memory, clock, and climate controls as required.

 

Awesome description Red..
Question tho, as is me... When doing a hard reset,,, with key in off position, are there lots of components that are out of or not included in the circuit to "drain" electrics - because the ignition is in the off position?

Without all of the (great!) procedural details you gave, I used to "reset" my car similarly - but what I would find is that some components (radio, trip computer, seat memory etc) would not reset with key off... I figured that the key might need to be turned to the run position, or to position two - to electrically include associated systems in the draining/reseting of electrical components....? Any merit to that idea?

 

Good point, Jay. I'm sure that there are instances when someone would want to reset every module, but I've found that my ECU issues have been addressed without turning the ignition to "ON" before shorting across. FIRST AND FOREMOST, ignition should certainly be "OFF" whenever disconnecting or reconnecting battery cables. Turning the ignition key to "ON" before shorting the cables (Neg to Pos) won't hurt anything; it will guarantee that all modules will reset and you'll have to retrain seat memory and etc, and you'll want to make sure that you've got the radio code in hand to save the frustration of finding out that you've locked yourself out of it. First time is always the scariest, but there are no sparks when you short the unconnected Neg cable across to the Pos (as no current flows through the battery itself). For those that are hesitant to short across the cables, you can accomplish the same thing by disconnecting the Neg cable and then turning the ignition key to "ON" for 30 min (then turn back "OFF" before reconnecting Neg cable). My Neg cable won't reach across to the Pos cable so I use a short piece of wire (or cut section of a wire coat hanger) to bridge the two cable connectors.

Check this out: JagRepair.com - Jaguar Repair Information Resource

One important caveat (ask me how I know...): A hard reset will prevent a car from passing a smog test for about 300 miles (plus or minus), as you'll get an INCOMPLETE until everything resets, so plan accordingly. Everything else will reset fairly quickly, (except things like windows, clock, seat memory and/or radio).

Note: Although I use the "Search Threads" box in the upper right hand corner to try to find specific item information in our Forum, I find that doing a Google search for things (like "hard reset Jaguar XK8") will easily and instantly bring up not only every pertinent thread in our Forum, but also tons of good info from other websites.

 

Amazing Stuff, Red! Thank you for YO thoughts...

And, a big +10 on your note, searching the forum and other sources.