I recently purchased a 2001 XJR. I got a great deal on it and figured something would come up needing fixing, and already I've got an issue. I'm a little perplexed on what it may be, since this is my first Jag, I thought I'd run it by the experts.

Here is basically what happens. When I start it up in the morning to go to work, or after its sat long enough for the engine to completely cool, the car turns on and cycles through all the dash lights. Everything goes off as normal. I then put the car into drive and by the end of my driveway, the performance restricted message with amber light come on. The car will not shift out of first gear. After driving between 2500 and 3000 RPMs to the end of my street (about 2 minutes), I can pull over, put the car in park, turn off the car and turn it back on, and the performance restricted light doesn't come on again. The car then performs as normal, with full engine power and transmission shifting smoothly as normal. This has been going on for about a week now and happens every time I start up the car after its been sitting.

I checked the engine codes the first time it happened, and got P0715 and P0100. The P0715 has to do with the transmission shifter being a little loose and not firmly engaging. The P0100 means the ECU didn't complete its check, I believe. I need to check it again and see if found something else.

Anyways, before taking this over to the mechanic I thought I'd see if anyone had experienced something similar and if there might be an easy fix. Because the car drives perfectly normal after turning it off and back on again.

Thanks,
Jonathan

 

I might as well be the first to jump in and ask how old your battery is. These cars can be very finicky about good voltage.

Does it crank slowly? Any other symptoms?

 

That's a good question about the battery... the previous owner had the car for about 3 years and said he didn't replace it. With that being said though, the battery terminals look clean and it doesn't look old. I also haven't noticed any other electrical issues.

The cranking speed seems a little slow, maybe 2 seconds to fire...

 

I have 8 cars. My wife and I don't drive all of them often and when any of the Jags sit for a week or more the INST PK display will usually fault something after crank/start.

I can run the engine for a minute or two and restart to get the display (and fault) to clear. I just accept the fact that the battery let the voltage drop to 'low-enough' to cause a 'voltage below threshold' symptom in various modules.

If I drive the Jags every day for a week, the fault never occurs. Just sitting dormant weakens the charge enough to 'confuse' the modules in the car.

bob gauff

 

The shifter being out of alignment can cause restricted performance to come on. The car is not exactly sure which gear you are selecting, so RP kicks in.

Try adjusting the cables to the shifter, zeroing it for proper alignment.

You can probably find the procedure here via the search function, or I am sure someone could post it for you.

And also check the voltage on your battery first, should be 13v+ when running. (I think 13.4v is the magic number, but I am not sure.) These cars have a lot of electronics and computers, and low voltage from a old battery or bad alternator drives them nuts.

Also, is it a P1000 or P0100 code you are getting? P1000 is normal, meaning the ECU has not run all its checks after a code reset, P0100 means a Mass or Volume Air Flow Circuit Malfunction, that could cause your RP too.
Vecor

 

"The cranking speed seems a little slow, maybe 2 seconds to fire..." There you have it.

Looking at the battery, and testing the voltage when running, are both really poor guides to the problem you might be experiencing here : low voltage when cranking. This is what happens when a battery gets old and its capacity drops. This problem usually shows up around this time of year, when temperatures drop. Battery capacity drops with temperature.

The best test is to measure the battery voltage DURING CRANKING. A healthy battery will maintain 10V or so under that enormous load of the starter.

Then it should rise to 14.4V or so when the engine is running, indicating a healthy alternator, but telling you nothing about the state of the battery.

 

let me answer about code P0715 from my personal experience

you need to replace the transmission conductor plate.

my cars started hard shift but I ignored the issue. one day, I learned it the hard way that tranny stuck between 3rd and 4th gear and I almost blew it. car was running 30 MPH but at near 5K RPM

search youtube, there is a video a MBenz guys thoroughly explains the entire issue. His videos saved my car.

Mercedes Transmission Conductor Plate Connector Filter Gasket 722 6 Genuine | eBay

 

So to follow-up to this thread, you were right about the code... it was P1000, not P0100 that the computer hadn't completed the check. The battery is at least 3 years old, so I picked up a new one yesterday and am getting ready to swap them out. Before I do anything else, I want to make sure I'm working with good juice. This is our 3rd car and it is only getting driven about 2 days a week.

About P0715, the shifter always firmly sets for me, light indicator is true, etc. I've never had any issues with the transmission not finding the correct while driving. I did find the post here about adjusting the cables, but I am not quite ready to pull apart the console and take this on. I also don't know how to measure nanometers of torque yet. :-)

 

It's not nanometers, it's newton-meters, similar to foot pounds, most torque wrenches had scales for both measurements.

1 newton meter = 0.7376 foot pounds.

Conversion tool here: Newton meters to Foot pounds Conversion Tool

Vector