Just changed the throttle body again (first one caused this: https://www.jaguarforums.com/forum/s...ad.php?t=49962) and now it idles only slightly high at 1,000 rpm and occasionally sputters up and down but usually levels off.

The problem is that it is in restricted-performance (aka. limp-home) mode with amber+red error lights and the check-engine light. What should I do now?!

 

I had similar problems and am now working on the purge system; so far, a lot cheaper than a throttle body. I'll let you know during the week what I've found/done. So far, the rubber hoses need replacing, and I'm checking the solenoid and vent valve ...

 

I had the same problem and I'm still growing the patches of hair that I pulled out.
My OBD said that it was the thortle body but because I couldn't afford one, I cleand mine yours is new so that wouldn't be your problem.
I also found that the underside of the intake hose was worn letting air in between the MAF sensor and the throtle body so I used some black duct tape and covered that.
The last thing I did was pull my wheels off, removed the wheel speed sensors, washed them with dish soap being careful not to get any inside the plug, reinstalled them and the problem has not come back.
If I do get that problem again the next step is to check the contacts where the Throtle body connects. I understand that sometimes the make poor contact after the engine get warm.
So far I have put over 400 miles on my 99 XJ8 and the problem has not come back.

 

vdp, after the throttle body change, did you have your codes cleared? if not, the restricted performance will take several drive cycles to automatically clear itself...and the drive cycle isn't down the street to the hooters either.

I recommend clearing the codes with a scanner/obdii reader. Then, do a hard reset, with a new throttle body, the trims will be outawhack and take awhile to readjust...the hard reset will force it to learn immediately, and may not have the delayed affect, resulting in RPM variations.

come back after you do that and report in. Understand soldier!?

 

Noooo I was told that disconnecting the battery a few minutes was supposed to do that?! My new code reader should arrive tomorrow, will be able to clear then.

Bloody blimey! Multiple drives in restricted performance?! I live in NYC, I will certainly be honked at within the first few blocks, nonetheless multiple drive cycles!

By hard-reset you mean battery disconnect, both terminals for a few minutes, right?

How long is "immediately"? A few seconds, a minute, 5-minutes? (When should I start to panick if it does not work?)

Sir yes Sir! Thank you Sir!

 

By hard-reset you mean battery disconnect, both terminals for a few minutes, right?

 

Have you cleared all the codes?

give the electrical system at least half an hour to drain residual current after unplugging the battery. Enough time to put the coffee pot on.

You'll notice engine rev's peak a bit higher than tickover on initial startup, this is to be expected as the throttle body recalibrates, don't worry. It climbs then falls to almost stall.

Next drive it round, mix the style up a bit with sport button on and off, the engine will adapt and gearbox also.

Hope it cures the engine lights. Good luck.

 

A hard reset/reboot is to disconnect battery doesnt matter if one cable both or which one. So long as at least one is unhooked, but then you touch and hold the disconnectted cable to the other. I useally disc the negative and hold it to the still connected positive. Theres no need to go through the issue of both. If you cannot reach then use the 10mm wrench in you hand to bridge the distance. Jaguar wants us to leave disconnected for a minimum of 5 minutes on the new cars, but ive never had issues with only 5-10 seconds. Remmebr to reset your windows and clock.


Sean, I just read your post after I posted the above, and if youre ever clearing transmission adaptations and a relearn, Jaguar recommends to NOT use sport for 200-300 miles

 

Codes reset then battery disconnected but unfortunately problem persists!

I had a p1229 code (and generic code p1000), after reset it still showed p1229 but now as a "pending code" in amber (before it was an active code in red) and it went right back into restricted-performance mode, even with the car-key in ACC (not running). When I did start it, it cycled through the learning process and leveled out with a 1200rpm idle (seems high, but okay).

I am using the "Torque" for Android to read the codes.

What should I do now??

 

Let me see if I understand this correctly. You replaced the TB and you have the same codes?

 

No different codes. Failed initial TB was P1122 (pedal position sensor - low) and that unit worked 99% of the time fine but would occasionally go into performance restricted mode while driving without any obvious pre-warning (dangerous on the highway).

First remanufactured replacement installed had idled at 4,000 rpm so pulled that out without checking codes.

Now the second remanufactured TB is installed and idles at 1200rpm (a bit high but okay) but is stuck in performance restricted mode with code p1229 "Electronic throttle control circuit" (if I clear it, it just comes back as an active-code when I start the car again). I unplugged and sprayed the plug ends with compressed-air and replugged (no difference). There is zero visible corrosion on them (like new actually, just a bit dusty).

If I remove the "breather-tube" and have the car in ACC (electric-on but not running) and press the throttle, the butterfly is supposed to open right? (it does not move).

 

I can confirm that the butterfly should open when the ignition is on (engine not running).

 

Lol, that can be read two ways:

You are confirming that it does open
or
You will confirm and then repost
?

Also, you don't mean that it should just stay in a fixed-open position, you mean that it should move when you push the throttle (or just rotate the pedal-position sensor on the throttle body) right?

 

Okay, sorry, I'm not an englishman in New York...

With the ignition on the butterfly moves (opens and closes) as you push/release the throttle.
In my case with no thottle it is a bit open (there is a small gap) and the servo motor is whining. I don't know if that is normal though.
When the ignition is turned off the butterfly closes completely.

David

 

Thank you David!

Indeed mine is dead and does nothing...

 

My code chart might be a little more in depth. The fault description is "Throttle Motor Control Circuit Malfunction;" Monitoring Conditions, "Ignition On/5 seconds;" Possible causes, "Throttle motor disconnected, Throttle motor to ECM drive circuit: Short circuit or open circuit, Throttle motor failure."

With the motor whining, it sounds like the a couple of the above can be eliminated. I would start looking for a short somewhere, or get another TB, as the short might be inside.

Is your engine an AJ26? If so, I have a throttle body, but off of a SC engine.

The numbers stamped on it are:

98JV
-9E926-AA

5294 10D09

See if the numbers match and we can continue from there.

 

I am thinking a little towards a bad rebuilt TB and I would be looking at a replacement. May I be so bold as to where or who you got it from? I am concerned with recommendations.

 

Hispeed, it was not my TB that was whining but rather David's, mine is dead silent (and probably dead altogether). My casting is 9E926-AE (air-assisted model C2A1444), your AA may not fit.

Gus, ordered from Jay Tan Industries - they are sending me another one. The people are exceptionally nice and helpful, so it is hard to be mad at them, but the third unit needs to work or I am going to give up and spring $1850 for a new one.

 

I do understand. Please keep us posted.

 

I wish you better luck with the 3rd one then !!!

And if the next one will not operate as well the problem is probably somewhere in the wiring.
As hispeed42 posted - Check the circuits...

The throttle motor definitely operates with ignition on (regardless of engine running or not).

And don't forget to clear the codes and do the hard reset after you changed the TB and BEFORE you start that engine with the new TB.

Good luck!


David