My XKR (124K) started displaying Restricted Performance, but there is no CEL and there are no engine codes (other than P1111). I even did a hard reset, and upon start-up I do get the Restricted Performance immediately along with no CEL or scan codes. I'm not really sure on where to start with this. I also drove around some hoping it may go away before and after hard reset.

I would like to note that about a month ago and ever since, I've gotten the dual console messages of "check rear lights" and "cruise not available" about 10% of the time. These most likely relate to a bad brake pedal switch which I simply have not got around to replacing. Can a bad brake pedal switch result in "Restricted Performance" with no CEL faults?

Any other ideas or experiences would be appreciated...as I'm really not sure where to start on this. Thanks.

 

Bill, Check the fuse to your intercooler aux. pump. I don't remember the # but it's located in the engine compartment on the passenger side close to firewall. You can also turn the ignition switch to on (engine not running) and open the bonnet to see if you can hear the aux. pump running---it's located just below the air filter box on the passenger side. The pump is about the size of a soda can.

 

Red1BW,

I replied to your PM before seeing this thread.

Do you leave your cruise switch in the 'ON' position? Mine started the 'Check Rear Lights' message that turned out to be the cruise sw. Doesn't do it when cruise is really operating, only when sw is on and cruise is not engaged.

 

MountainCat - the supercharger inter-cooler works. I checked with a car stethoscope (mine is fairly quiet, but does hum and can even hear the fluid going through the inter-cooler / pipes) and also checked every fuse in the car (all 5 fuse boxes) with ohmmeter. I'm not sure why this didn't occur to me...checking fuses... but it didn't. Thanks.

Test Point: Ensured Cruise Control was off / cancelled (right side of steering wheel controls). In fact my cruise control worked fine in restricted mode, but I did ensure it was off before parking again. Thanks.

Hard reset...did again and for much longer. Turned car on, and went to restricted performance with ignition on before even cranking engine. Also, when code reading pulled up P1111 (why the heck would P1111 be showing instead of P1000 after a battery disconnect / master reset)???

Any other ideas or help would be appreciated....the only guess I have at this point would be to change out my brake pedal switch...but I haven't even ordered that yet...and am somewhat shocked that that would cause this.

 

Install your OBDII reader and check the codes document them then take the car for a run with the OBDII installed as soon as you get the restricted performance check the OBDII reader and see if it captured the code.

 

A battery disconnect will not force P1000, only a code reset operation will.

I think you should go ahead with the brake switch repair before doing anything further, since it is a dual contact switch that the ECU does monitor for the cruise control.

 

Bill,

There's a good likelihood your code reader can't read a corporate fault code like P1571 that could exist in you car. It's not an OBDII fault code so some scantools can't display it.

Your choices are find a better scantool or throw a dart and replace the brake switch.

Good luck!

 

I had two knock sensors give me the restricted performance with no codes. The first one took about a month to find the second one I found when I had the OBDII plugged in. It seems the code will not set until it sees the problem twice in a certain time period. Yes the P1111 will stay until the on board diagnostic test is completed.

 

Thanks all for the input.

WhiteXKR: I've always assumed that a battery disconnect would reset P1111 to a P1000 since it clears CEL's. That is very interesting that it keeps the P1111 self checks completed (even after hard reset) unless specifically reset / cleared.

XJRguy: I think you're right unless there is some ECU / computer glitch. JTIS makes clear that there is a finite set of P-codes that cause the dash to display "Restricted Performance" with amber light. Most likely, my XKR is doing this because it is suppose to be doing this. Would be easier to troubleshoot if I could see the reason it is displaying "Restricted Performance." I even bought a WDS some time ago, but have been unable to find Jaguar software for it.

Anyways...knowing I have a brake switch going bad...it only makes sense to replace, as I would have done that anyways. Since no local parts store stock it locally, it may be a week+ before I replace and this saga continues.

 

Try the OBDII in the car and see if it picks it up you have nothing to loose. It has worked for me and others.

 

Gus - I will try that tomorrow. I am 90% sure I had my OBD plugged in after the hard reset / battery disconnect, and when I turned the key to ignition on, "Restricted Performance" came on with no codes... but I will keep my OBD II plugged in tomorrow while driving it for a while in the hopes something does show up. Thanks.

 

Jaguar has several codes that are invisible to the standard OBDII code readers we are all using. It is with high hopes you get a code but as suggested it may not read it but no harm in trying.

 

Gus - good idea, but I didn't have any luck. I drove around for about 45 minutes continuously pressing "read" on my Actron code reader - and only got my P1111 each time. Also on this 45 minutes drive, it switched from only "restricted performance" to "restricted performance" and "check rear lights" and "cruise not available." So i sorta doubt that a new brake light switch will fix the sole "restricted performance" but that is clearly one of the next steps.

I ordered a new Brake Light Switch today and will probably receive it next week. Till then, I may try another generic code reader if I can get my hands on one. Thanks all, and will still take other ideas.

 

Another update - may tell nothing:
I unplugged the brake light switch completely and got the same restricted performance.
I plugged a brake light switch from a 98xk (different part - visually different, but similar) had no part number on it) and still got restricted performance.
For these steps I never uninstalled the original semi-broke one, never installed the other one, never put the brake bar in the switch, and never set brake travel limits (if needed).
Plugged the original brake switch back in, still same "restricted performance."

I tell you, I'm not sure if my Hyundai Elantra is more powerful than the XKR in restricted mode or not. Now comes the hard part....let XKR sit and wait for part to get shipped here.

 

I would wait, do the switch replacement before doing any more theorizing. One issue at a time.

 

+1

 

A generic reader will not read a trans temp code(mine wont) and thats another issue thatll throw you in rp. Maybe since it so constant you should go to a dealer and have it scanned with genrad or sdd just a thought

 

Do you have your foot on the brake and is the cruise control on when you start the car and get the restricted performance? If not I would be looking else ware for the problem. Have you changed cleaned or modified anything prior to your getting this RP?

 

WaterBoy- all I can do is theorize until the new brake part comes. Didn't you read....I'm now driving in an Elantra.

Brutal - another great Forum member about an hour away has just offered to read my codes; that will be the first thing I do if I still have RP after installing the new brake switch. However, when I drive the car it does clearly shift through its gears (I didn't count, but I believe it has access to all of em). Of course that doesn't rule out all the transmission possibilities, but the transmission doesn't go to one of its safe gears or cause limp home. There's a code in there somewhere, and JTIS shows many of those P codes >1000 that cause RP.

Gus- RP comes on during the cars self checks...even after a hard reset before the engine is even started (but key is turned to ignition on position where car conducts self checks). Cruise was definitely off. However, I may have had foot on brake as it is habit to me when starting car.

For those interested, in JTIS the brake switch is referred to as the BPP switch, Brake Pedal Position switch. This makes it much easier to global search. It appears to have 2 switches within the BPP: one for the brake lights directly, and one to tell the cars CPU if the brake is pressed (and probably how much it is pressed as it does have 4 wires coming from it). The CPU can then disable cruise control, disengage the lock up converter, probably recognize emergency stopping; and I would assume use the brake information / position information for many other reasons. Thanks all.

 

This is a switch replacement procedure along with what the switch looks like.

Link JagRepair.com - Jaguar Repair Information Resource