I have a 2010 supercharged XKR Jaguar sports car which I bought new ten years ago. I also owned an earlier version of the Jaguar sports car from 2000 to 2010. Just to put the standard responses to rest I have never "big footed" either of these cars (or any other cars) over many years of driving. I do plead guilty to the second standard response that I am 81 years old but I am physically fit and mentally alert for a person this age. I am interested in responses that might relate to other people having the same technical problem.

Now, let's get to the problem. One morning I enter the car, step on the brake, and push the start button. The car is in "park". The engine revs at a high rate of speed for one second and then drops immediately to normal idle speed. I am surprised but because the engine is at idle speed I back out of the garage. I drive to my appointment and back home and the car acts normally. The next day I drive the car and the car acts normally.

The third day I start the car normally and drive to a gas station. After filling up the car with high octane fuel, I get in the car and when I start it, the engine goes into high rev for a second and drops immediately down to normal idle speed. So far I have not touched the accelerator with my foot. I simply rotate the shift knob into drive. The engine instantly goes into maximum rev without me touching my foot to the gas peddle. In shock, I stand on the brake with unknown results. The car is stopped by a post 15 feet in front of me. I turn off the car, talk to the station manager, then restart the car and it sounds normal so I drive home. Upon arriving home I restart the car twenty times to see if I can recreate the high rev situation. The car acts fine.

Has anyone else had the situation of their Jaguar engine going into high rev when in the "park" mode or after shifting to "drive"? I would greatly appreciate any advice I can get!!

Steve Moksnes

 

Welcome to the forums Steve,

You post was automatically locked for moderation. I've removed your email address and unlocked it.

Graham

 

Steve - I don’t have an answer for you, but wanted to thank you for such a well written description of the problem.
It should ward off the naysayers that jump in on ‘sudden acceleration’ issues and say it was operator error, foot on both the brake and gas at the same time, gas pedal stuck in a floor mat, etc.

 

I have to agree on both counts. Sorry to hear about your "event" at the gas station. I've not experienced your problem yet - and hope not to.

Given how thoughtful you are, you've probably thought of this but...as a work-around until the problem is fixed, apply maximum braking every time you shift out of park.

Also, has this happened when shifting into reverse from park?

 

The gas and brake pedals on my XKR are very close to each other, and it is possible to accidentally depress both simultaneously. I inadvertently did this once, years ago and it was scary! The harder I pressed on the brake, the faster the car revved up (until I realized what I did). Fortunately, no harm done.

If you depress the brake pedal hard with the left half of your right foot on the right corner of the brake pedal, the right side of the sole of your shoe will contact the gas pedal and cause unintended acceleration. That's a real problem if your shoe size is 11EEE!

Remember to always center your right foot on the brake pedal so you don't inadvertently press the gas pedal.

This close-pedal design probably goes back to the days when Jags had manual trannys and racers used the heel-toe technique while downshifting. The pedals on my wife's MDX are much farther apart.

You can also avoid this problem simply by pressing the START button first, before you step on the brake pedal. All you need is a light tap on the brake and it'll start right up. Yes, I know that's the opposite of what the Owner's Handbook says, but trust me, it works.

 

I hate to say it, but I also had one bout of sudden acceleration. Sure enough, my foot had just barely caught the edge of the accelerator pedal.
I'll not do that again (hopefully).

 

Just press the START button first, before you step on the brake, and it won't happen again because your foot will not be on the gas pedal when the engine starts.

 

The Jaguar X150 uses an electronic "drive-by-wire" system to control the throttle (gas pedal) position. There is no mechanical linkage between the gas pedal and the engine, and various electronic sensors enable the ECU to determine fuel delivery. That system includes safeguards to prevent unintended, sudden acceleration.

Is X150 sudden acceleration possible without driver error? I haven't found any credible evidence to support a "Yes" answer, so my answer is "Probably not."

See:
https://www.jaguarforums.com/forum/x...ration-182227/

https://ieeexplore.ieee.org/document/639984
"Abstract:The electronic throttle is a major innovation of the AJV8 engine in the Jaguar XK8 vehicle. Although essentially transparent to the driver, it moves Jaguar into new territory, and has often been referred to in the past as "drive-by-wire". Jaguar, in partnership with the Denso Corporation, has developed a system that while still offering a simple mechanical solution to assuring overall safety, also recognises the importance of the increased criticality placed on computer controls. This paper discusses both the system safety concepts, and describes the state-of-the-art methods that have been used throughout the development of the XK8."

See also:
https://en.m.wikipedia.org/wiki/Sudd...d_acceleration

 

I have also on three or four occqsions pressed the brake pedal and the edge of my gas pedal while in drive, and it scared the hell out of me, especially since when it happens you don't realize your foot is on the gas so you keep pressing the brake harder which, in turn, presses the gas pedal harder before you understand what you've done. But the OP seems to have a different problem probably related to the fuel injection system.

 

The first time the high rev happened in "park" I was in the garage and when the engine immediately dropped to idle speed I shifted into reverse and the car acted normally. Thanks for the question. Steve

 

Welcome Steve, 10 years original owner, that is a rarity on this board!!!

This same issue has been reported in the past, most responses like you see so far have always focused on operator error which has validity. I don't know that it was ever resolved by the previous complainants, but in one instance a person reported the issue was fixed with a software update by the dealer, the link below will start you at the relevant Post #26 by Robert Page. Feel free to scroll the rest of the thread also:

Sudden acceleration !! - Page 2 - Jaguar Forums - Jaguar Enthusiasts Forum

 

Just something to try from here out.
Use your left foot on the brake to start the car with it on the left side of the pedal.
I also find that what Stuart suggested of hitting the start button then the brake pedal seems to be how the car was programmed to work.
This, despite it saying the oppisite in the manual.
Liekly whoever wrote the manual and whoever programmed that aspect of the car last didn't get in touch in time.

 

The reason responses immediately go to "foot on gas and brake" is the situation is happening at a moment of intended pressure from a foot.
And it isn't just age, younger people can do it to.
I did it in my Corvette, was wearing a pair of hiking boots I'd never worn to drive that car.
They were just that much wider.

 

I just did the ABS module soldering trick. All seemed to go well until I started the engine and had to shut it down because of extremely high revolutions. Did I bend a pin when I reinstalled the module or do I have a new problem.

 

Are you in the right Forum? This is the X150 Forum, for 2007- 2015 XK/XKR models. Your Public Profile shows that you have a 2000 XK8, which is the previous X100 model. Their drive-by-wire throttle systems are not identical.

If you didn't intend to post here, then you're probably a victim of "Infinite Scroll", a feature that many Forum members dislike.

 

As mentioned above, the throttle is "fly-by-wire". It therefore can't be a mechanical issue where a cable is sticking. This leaves two plausible options:

1. a fault with the APP (Accelerator Pedal Position) sensor
2. fault in the throttle actuator control - jammed throttle blade, gearing or motor circuit

To progress with this you need to run a SDD diagnostics session for relevant DTC's.

Graham

 

It appears that there have been no recalls or Technical Service Bulletins affecting 2007 X150 models for sudden or unintended acceleration. There was 1 report of unintended acceleration while braking. See:

https://www.nhtsa.gov/vehicle/2007/J...2%252520DR/RWD

 

Hi Stuart, I sold my 2000 XK ten years ago. My present model is a 2010 XKR. Steve

 

Hi Steve,

My Post #15, above, was in reply to a post by larry minor, whose Public Profile shows that he has a 2000 XK8.

I know that you have a 2010 XKR, which you clearly stated when you started this thread You also explained that you sold your XK8 and that you never "big footed" either one in order to put that possible cause to rest. Nevertheless, my experience and the experiences of others suggest otherwise.

Sudden, inadvertent acceleration by definition means that you're unaware of the cause, including that you might not realize that you did it. Try to be open to that possibility.

Have you tried my "press the START button first" recommendation in Post #7, above? If so, and you still experience the same sudden acceleration, then follow Graham's advice in his post #16, above.

Otherwise, blame your shoe.

Stuart

 

Steve,

I'd like to clarify my post #4 in this thread. Rather than edit it, I am posting again to bring it to the top of the thread.

In applying maximum braking, better to use your left foot and keep the right one out of the equation. That way there is much less risk that your right foot will engage both brake and accelerator pedals. Apologies in advance if this is too obvious!