I have been seeing several Restrictive Performance (RP) posts and wanted to see if we could ask those who experienced this event to post the event and the cause found. RP is a result of a problem! It could be from air intake to knock sensors, MAFS to Throttle Body and a host of many other things. Often the RP will provide a Diagnostic Trouble Code (DTC) other times it will not. Can you help by providing your situation?

 

I've had one - a recurring throttle modulation (engine would accelerate/decelerate with no throttle pedal motion - often when at idle) followed within seconds by Restricted Performance and a litany of error messages - Traction Control, Transmission, ABS, etc. It would reset by shutdown and restart and then drive fine. No codes thrown.

Original occurence was followed by same thing about a month later, both occurred during rain. As time progressed, and the rainy season continued, the identical events got closer and closer together until finally it would not go away with a shutdown reset; and THEN, finally threw a CE code - P0121 - TPS signal out of range.

From the code, I traced it to the throttle position sensor connector - mine still has the tin contacts on the harness connector with gold in the TPS. A good cleaning of the connector pins (both ends) with contact cleaner/lubricant, in my case from Radio Shack, immediately fixed the issue and it has remained that way for three months now. I will be replacing the tin pins with gold replacements shortly, but at least I have an interim fix.

 

I had a reoccurring RP problem that would set the P0171/074 (lean left/right) codes and then go away only to come back another day. Found the 'bellows' section of the duct from the air filter to the throttle body had cracks causing the occasional lean condition.

 

When I had the TB plug problem I got a Fail Safe message not Restricted Performance. This is definitely another area of concern. A little info on the TB plugs 1999 – 2002 XJ & XK TSB 303-58 http://www.gusglikas.com/AutoRepTB.htm

 

I apologize, Gus, it most likely WAS a Fail Safe, not a RP... Car would not drive at all, had to pull over and restart, so I assume that's Fail Safe, yes? I didn't realize there were the two different modes of operation under a failure. And yes, your TB page was one of the references that led me to find the probem - thanks!

Interestingly, I had another Fail Safe today - it's been a while. This one a Traction Control loss and ASC loss... happened when I pulled out of a driveway - most likely a wheel sensor or sensor link (pot hole like) issue? Reset with shutdown and restart. No codes thrown, nothing in the additional 60 miles driven.

 

I had one. Due to the plastic cover for the coils not sealing properly due to a bad screw thread that was allowing moist/water to get into one of the coils and spark plug. After removing and drying those, I did a temporary fix to the cover by putting some black duck tape on it to make sure no water gets in there through the crack again.

 

I'm currently getting the too lean bank 1 & 2 code. Partial throttle results in rumble and stumble but little acceleration. Full throttle overcomes hessitation. Sometimes it acts worst then others. It seems less appearent soon after starting. Any Suggestions?

Possible causes:
I did replace a failing coil due to water intrusion and 3-4 others have rusty marks.
I did clean the Mass flow sensor and throttle body with throttle spray cleaner.
I did recently replace the motor (1000 miles ago) so everything has been opened up.

 

I read some additional posts and a quick few sprays of the CRC MAFS cleaner got rid of my hessitation. It now purrs and all the rumbling is gone. Thanks everyone for all the helpful posts that have been left on this site!

 

I bought an obd2 reader from advance auto for 69$ on sale cleared all codes and then drove my car, 02 Xkr, then checked the codes again and got p0171 & p0173. Cleaned my MAF with MAF cleaner, checked air intake hoses for leaks and reset codes then drove around for 3 hrs and all is good! Less than 8$ for cleaner and 15 minutes of work. I bought the code reader and still spent less than what the dealership and local garages wanted just to read the codes!!!!!!!!!!! I hope this helps, now let's go driving!

 

Money well spent and a great deal of satisfaction. Kudos to you!

 

On my 2002 XK8 the check engine light came on and it's also giving me Restricted Performance warning but only occasionally. When it says that the car will not accelerate smoothly if I give it too much gas. I checked it today and am getting P2199 code Intake Air Temperature sensor. It says there is a correlation error in the IAT sensor. It also indicates that the OEM brand is Ford. I can't seem to find any info on the forum about this and when I try to find the part on line no Jag parts dealers seem to recognize the name. Any help? As always, thanks in advance. This forum helps me keep my sanity.

Buck

 

Do yourself a favor and go to AutoZone, PepBoys or whatever and verify that code please.

 

Old post and Wrong forum.

bob gauff

 

Gus I got the code at AutoZone. Didn't realize I was out of the XK8 area. I'll repost this as a new thread.

 

I got a restrictive message once yesterday, then in the evening arriving from my 2 mile commute got--- ASC, and TRAC not available.

Not sure whats happening.

Did a TB clean a few months ago.

 

Did you check and clean the TB plugs?

 

I occasionally get the ASC and TRAC NOT AVAILABLE messages. Usually when it has rained or the car has sat for a time. If I start the engine a couple of times on a dry day, it goes away. I believe it is caused by dirty ABS sensor(s) and/or sagging battery voltage. On my car, I plan to clean the ABS wheel sensors when I get around to it. I think the rear ones are more susceptible to dirt than the front ones.

If the messages stay on always, then look for ABS module trouble, either poor connection at the connector or failing solder joint inside the module. This is discussed various threads.

 

First off I wanted to thank all in the forum - specifically Gus, the Moderator, for providing information here. My XK8 in general has been a really reliable car and aside form the consumable items (namely - arrghh the expensive tires) I have had very few issues. Unless we talk about the 2004 XK8 that would stop with no reason and Jaguar had to declare a lemon. That's another story altogether.

About 2 weeks ago the DSC warning light came on but since the oh-so informative owners manual said the car can be driven and the light went out, I didn't worry. Yesterday, the "Restricted Performance" popped up and again - car can be driven - but now I *was* worried. I had noticed a loss of power while on the highway and kept checking if the sports button was maybe not engaged.

When reading Gus' post with the various possible causes, a friend and I decided to look at the air filter first. To our surprise, the Throttle Body air intake hose - the accordion section - was badly cracked and just about crumbled at the top ridges, like rusty metal. The bottom side showed no sign of cracking.

Off to Safeway, only store open at 11pm, to pick up duct tape. My friend was able to very carefully wrap the section and the car is currently at the dealer. I am awaiting a call to see if the codes showed any other issues but it was very clear what the problem was.

I asked the service guy if that was a common occurrence and he said he had not seen many of these failures except once or twice on older XJ models. Is it possible that part was defective to begin with?

I have some pictures of the cracked area as well as of the "hillbilly" repair - Safeway only had shocking pink duct tape - so the pictures are not only educational but also quite amusing. Unfortunately I do not see a way of sharing them here?

Update:

So, yes the mechanic got a chuckle from the repair we did - but I cringed when he quoted $165 to read the code and $217.00 for an "intake tube" and "air duct".

There was another code -I had seen a message flash by quite a while ago about "loss of cruise control" (ignored it since I don't use it much) BUT ... he said I needed a new stop brake switch and new brake ped switch , another $200.

And if all that wasn't enough there was apparently a coolant leak and now I really cried - needed a new Thermostat Tower Assembly.

Moral? I will never ignore another message from my Jag!

 

Sure you can! But first I need you to introduce yourself on the new member section, with that and a few posts you will be able to post your photos. Yes, Go For It! Also thanks for your comments. It is always good to know I did something right.