Sudden Full Throttle Acceleration
Junior Member
Joined: Sep 2020
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From: Washington DC
Discussion # 1
THANK YOU to all who have offered constructive opinions on the failure I experienced with my '99 XK-8 . I finally was able to check into the battery and alternator conditions. Testing battery voltage at the terminals while shut off showed 12.22 volts, and while idling showed 13.1 volts. I pulled the cables, which looked fine on the outside, and did a battery load test. Battery checked out fine. Close inspection of insides of both cable clamps showed pretty severe discoloration and deposits, which were not evident on the outside. After cleaning off all corrosion of clamps and battery posts, the voltages are now 13.25 (off) and 14.2 (idling). I also cleaned throttle body interior, which on test drive helped smooth out acceleration from a stop. Other systems on the car are now working more smoothly, such as window motors, auto. str'g. wheel adjustment, etc.
By the way, the car has the later all-electronic throttle body/cruise control. I'm now thinking that the lower voltage available to the computers and sensors may have caused the sudden-full-throttle glitch that I experienced the other day. In test driving after these fixes, the car is much smoother in performance. I made multiple test stops to replicate what had happened originally, and the car behaved perfectly each time. I'm going for a longer drive today to further test it, but I'll be ready to kill the ignition if necessary...
Again, THANK YOU to all who jumped in to try to help me and didn't accuse me of confusing the brake and accelerator pedals! If it happens again, I'll certainly let you all know (if I survive it...).
By the way, the car has the later all-electronic throttle body/cruise control. I'm now thinking that the lower voltage available to the computers and sensors may have caused the sudden-full-throttle glitch that I experienced the other day. In test driving after these fixes, the car is much smoother in performance. I made multiple test stops to replicate what had happened originally, and the car behaved perfectly each time. I'm going for a longer drive today to further test it, but I'll be ready to kill the ignition if necessary...
Again, THANK YOU to all who jumped in to try to help me and didn't accuse me of confusing the brake and accelerator pedals! If it happens again, I'll certainly let you all know (if I survive it...).
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Joined: Jan 2021
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X Type Sudden acceleration is real
Hello All. I’m new to this forum.
2004 X Type. The problem is real and dangerous.
It happened twice. When completely stopped and the brake pedal applied, the rpm surged suddenly. The second time, when applying brakes to slow down as I was approaching a red light. I’m afraid of driving the car now. Has anyone found a fix? Any help is much appreciated. Thank you.
2004 X Type. The problem is real and dangerous.
It happened twice. When completely stopped and the brake pedal applied, the rpm surged suddenly. The second time, when applying brakes to slow down as I was approaching a red light. I’m afraid of driving the car now. Has anyone found a fix? Any help is much appreciated. Thank you.
Veteran Member
Joined: May 2019
Posts: 1,092
Likes: 927
From: Durham, NC
Interstate 95, 10 pm, needed to turn the car back on at highway speed after a 'CAN bus stall' (now fixed). Since I was very focused on fixing the problem without being run over, I gave no warning, scared the crap out of my daughter...
Not particularly recommended.
Not particularly recommended.
Veteran Member
Joined: May 2019
Posts: 1,092
Likes: 927
From: Durham, NC
Hello All. I’m new to this forum.
2004 X Type. The problem is real and dangerous.
It happened twice. When completely stopped and the brake pedal applied, the rpm surged suddenly. The second time, when applying brakes to slow down as I was approaching a red light. I’m afraid of driving the car now. Has anyone found a fix? Any help is much appreciated. Thank you.
2004 X Type. The problem is real and dangerous.
It happened twice. When completely stopped and the brake pedal applied, the rpm surged suddenly. The second time, when applying brakes to slow down as I was approaching a red light. I’m afraid of driving the car now. Has anyone found a fix? Any help is much appreciated. Thank you.
Then there is neutral.
Then there is the key into position 1.
All of these will work independently, so, safety shouldn't be a particular concern. On the other hand, are you sure you did not clip the accelerator when you pressed on the brake. Most unintended acceleration events have been found to be either foot on wrong pedal or foot on both pedals (there is a now a 'black box' capability for crashes which takes often mistaken human memory out of the equation).
Beyond that, you might want to ask the X-type forum (this is the XK8/R forum) and look at the NHTSA complaints (US Department of Transportation) for the X-type on the internet for unintended acceleration.
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Member
Joined: Jul 2012
Posts: 45
Likes: 19
From: Tucson, Az.
I had similar issue on my 99 XK-8. Removing the battery cable clamps and cleaning them as well as the posts on the battery (after load-testing the battery to determine condition) seems to have fixed the problem. No other instances for me in the last year or so. Check voltage at batt. with cables on, then again after removing, cleaning and re-installing them and note if there is a voltage increase.
Junior Member
Joined: Nov 2018
Posts: 3
Likes: 0
From: wilmington, ma
Unintended acceleration for sudden full throttle acceleration.
This happened twice to me.A 2006 jaguar vanden plas.
It was my 1st and last jaguar.When I bought it had
Undercarriage damage .
And I did not know the cause.I did find out though.
It happened twice.The 1st time I nearly Tbonedboned A big truck.But I got lucky and was able to stop it.Second time I was not so lucky and I rear ended a car with little baby in it.Second
There's no sure fix.That is why I think jaguar is ignoring the problem. The second incident Was after I spent $3,500 on maintenance on the car.I was 5 miles from the shop.
I sold the car for parts.If I could have afforded , it I would have crushed it.
Of course the accident was my fault And I'm disputing it with the state insurance boarda....using the argument that the 3rd factor in the in the accident was automobile mail function on the fly by wire software.
Does anybody have any advice on how to approach this?New .
It is not a minor mechanical defect the car is a time bomb.If you have 1 and you have the problem once . I suggest you dump it before it dumps you.
It was my 1st and last jaguar.When I bought it had
Undercarriage damage .
And I did not know the cause.I did find out though.
It happened twice.The 1st time I nearly Tbonedboned A big truck.But I got lucky and was able to stop it.Second time I was not so lucky and I rear ended a car with little baby in it.Second
There's no sure fix.That is why I think jaguar is ignoring the problem. The second incident Was after I spent $3,500 on maintenance on the car.I was 5 miles from the shop.
I sold the car for parts.If I could have afforded , it I would have crushed it.
Of course the accident was my fault And I'm disputing it with the state insurance boarda....using the argument that the 3rd factor in the in the accident was automobile mail function on the fly by wire software.
Does anybody have any advice on how to approach this?New .
It is not a minor mechanical defect the car is a time bomb.If you have 1 and you have the problem once . I suggest you dump it before it dumps you.
Senior Member
Joined: May 2020
Posts: 257
Likes: 131
From: Columbus
I reply to both track this thread and share what you can easily find by Google search... it seems there are a few stories about a Jag sudden acceleration issue. The first few words of each passage takes you to the online source.
The primary reason that you might face unintended acceleration when you are braking is that the electronics in your Jaguar are malfunctioning, specifically the electronics that control your powertrain. When this happens, throttle mechanisms don’t function properly. Obviously vehicles are manufactured as safely as possible today and there are throttle control mechanisms built into newer models of the Jaguar and other makes. However, malfunctions happen, so sudden acceleration remains an issue and it is important that as a driver you understand how to deal with it.
We are desperate to track down this problem as the dealer insists he take this dangerous car back and won't let him out of the lease unless he pays off 75 thousand dollars first! Keep in mind that he recently traded in another Jag for this new one. His last one was a (2002 I think) Vanden Plas. It was one of those stretch models, he did not have similar problems with it. But did have other problems like wind noise in the back side windows.
I have a 2013 XJ - 5000 miles. Yesterday and today I had frightening issues of acceleration where the gas pedal stuck to the floor. Only way to keep the car from moving was standing on the brake. Managed to get the car into neutral and then turn it off. When I turned it back on again, it went to over 5000 rpms. I let it sit, in the middle of the road, for a few minutes and tried again.
Data PDF from NTSB: unintended acceleration; and provide law enforcement with a practical means of ... patterns and driver causes of crashes involving pedal misapplications (NTSB, ... Jaguar. 4. 2. 0. 0.17%. 0.41%. 0.00%. 0.22%. Jeep. 59. 15. 0. 2.47%. 3.05%.
The primary reason that you might face unintended acceleration when you are braking is that the electronics in your Jaguar are malfunctioning, specifically the electronics that control your powertrain. When this happens, throttle mechanisms don’t function properly. Obviously vehicles are manufactured as safely as possible today and there are throttle control mechanisms built into newer models of the Jaguar and other makes. However, malfunctions happen, so sudden acceleration remains an issue and it is important that as a driver you understand how to deal with it.
We are desperate to track down this problem as the dealer insists he take this dangerous car back and won't let him out of the lease unless he pays off 75 thousand dollars first! Keep in mind that he recently traded in another Jag for this new one. His last one was a (2002 I think) Vanden Plas. It was one of those stretch models, he did not have similar problems with it. But did have other problems like wind noise in the back side windows.
I have a 2013 XJ - 5000 miles. Yesterday and today I had frightening issues of acceleration where the gas pedal stuck to the floor. Only way to keep the car from moving was standing on the brake. Managed to get the car into neutral and then turn it off. When I turned it back on again, it went to over 5000 rpms. I let it sit, in the middle of the road, for a few minutes and tried again.
Data PDF from NTSB: unintended acceleration; and provide law enforcement with a practical means of ... patterns and driver causes of crashes involving pedal misapplications (NTSB, ... Jaguar. 4. 2. 0. 0.17%. 0.41%. 0.00%. 0.22%. Jeep. 59. 15. 0. 2.47%. 3.05%.
Junior Member
Joined: Jan 2021
Posts: 7
Likes: 0
Is it an ECM programming issue? Does anyone have any idea what causes it? or probable causes? Is there any software update for the X-Type maybe?
One would think it may not be too hard for manufacturers like Jaguar or Ford to implement a system to override this: If brakes are applied then bring down rpm to idling. Some kind of a system either mechanical or electronic to achieve that and override an rpm surge or a full-throttle condition if it happens while brakes are applied. Similar to disengaging Cruise Control when brakes are applied.
I hope X-Type owners on the forum who may have experienced the issue can share any info or fixes or direction to what to look for or how they managed to live the problem (if that is what we end up doing?). I absolutely love the car, but this is a dangerous problem.
Thank you all for your input and replies
One would think it may not be too hard for manufacturers like Jaguar or Ford to implement a system to override this: If brakes are applied then bring down rpm to idling. Some kind of a system either mechanical or electronic to achieve that and override an rpm surge or a full-throttle condition if it happens while brakes are applied. Similar to disengaging Cruise Control when brakes are applied.
I hope X-Type owners on the forum who may have experienced the issue can share any info or fixes or direction to what to look for or how they managed to live the problem (if that is what we end up doing?). I absolutely love the car, but this is a dangerous problem.
Thank you all for your input and replies
Veteran Member
Joined: May 2019
Posts: 1,092
Likes: 927
From: Durham, NC
Is it an ECM programming issue? Does anyone have any idea what causes it? or probable causes? Is there any software update for the X-Type maybe?
One would think it may not be too hard for manufacturers like Jaguar or Ford to implement a system to override this: If brakes are applied then bring down rpm to idling. Some kind of a system either mechanical or electronic to achieve that and override an rpm surge or a full-throttle condition if it happens while brakes are applied. Similar to disengaging Cruise Control when brakes are applied.
I hope X-Type owners on the forum who may have experienced the issue can share any info or fixes or direction to what to look for or how they managed to live the problem (if that is what we end up doing?). I absolutely love the car, but this is a dangerous problem.
Thank you all for your input and replies
One would think it may not be too hard for manufacturers like Jaguar or Ford to implement a system to override this: If brakes are applied then bring down rpm to idling. Some kind of a system either mechanical or electronic to achieve that and override an rpm surge or a full-throttle condition if it happens while brakes are applied. Similar to disengaging Cruise Control when brakes are applied.
I hope X-Type owners on the forum who may have experienced the issue can share any info or fixes or direction to what to look for or how they managed to live the problem (if that is what we end up doing?). I absolutely love the car, but this is a dangerous problem.
Thank you all for your input and replies
However, my suggestion is to discuss this in the x-type forum (as you have appeared to have done).
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Joined: May 2009
Posts: 27,505
Likes: 4,902
From: Yorkshire, England
The X-Type (as with S-Type and I expect other jags) has a data logger which should be read to determine the commanded acceleration and sensor values. (No-one making these claims ever seems to read these values!)
Veteran Member
Joined: May 2019
Posts: 1,092
Likes: 927
From: Durham, NC
Tesla just went through this. Numerous claims. Investigated by NHTSA (US Department of Transportation) using the logs in the car. All claims were found to be misapplication of the pedal (i.e. driver error).
Bottom line, if you find you are accelerating (or RPMs are increasing) when braking, move your foot to the left and try again.
Senior Member
Joined: May 2020
Posts: 257
Likes: 131
From: Columbus
Veteran Member
Joined: May 2019
Posts: 1,092
Likes: 927
From: Durham, NC
Otherwise, I'd be accelerating straight into oncoming traffic in the UK, Aus, Japan without knowing it while rooting around for the clutch somewhere. It's hard enough avoiding shifting with the door handle.
Member
Joined: Feb 2013
Posts: 32
Likes: 3
From: albuquerque new mexico
I have been reading these posts about unintended acceleration for a while now. It has happened to me in my 2003 XK8, though not full throttle. It feels more like the cruise control is engaged, even though I have not engaged it, just driving in the city. I have had the car accelerate while parking. I have had it accelerate with my foot off the gas. I notice that if I press the cruise control cancel button, the car will stop accelerating and slow down with my foot off the accelerator. Anyone on this forum who suggests that drivers are somehow mistaking the brake and gas pedals, or somehow have such wide feet that they can't help but press both pedals at the same time, are condescending SOB's who should shove their opinions up their throttle bodies with both hands!
My problem with acceleration is not yet solved. It is intermittent. But the fear of driving the car is real. I will try the battery connection solution and see what happens, and report back, if I haven't been canceled from this forum. But please stop suggesting that we don't know how to drive. I have owned a lot of cars over the last 50 years, and this is the only one with which I have experienced this issue. How about trying to help solve the problem instead of insulting the posters.
My problem with acceleration is not yet solved. It is intermittent. But the fear of driving the car is real. I will try the battery connection solution and see what happens, and report back, if I haven't been canceled from this forum. But please stop suggesting that we don't know how to drive. I have owned a lot of cars over the last 50 years, and this is the only one with which I have experienced this issue. How about trying to help solve the problem instead of insulting the posters.
Senior Member
Joined: May 2020
Posts: 257
Likes: 131
From: Columbus
Good day kramzerreitug, you woke up a two year old thread with your well intentioned rant. The rant inspired me to re-read this entire string, as your characterization of "condescending SOB's who should shove their opinions up their throttle bodies with both hands!" is curious. The posters on this thread are all quite helpful. Out of the 55 posts in this thread, there is only one or two asking about possible foot pedal error. This is hardly deserving of your prescribed shove up their throttle body. My hypothesis is you could consider an alternative place to vent your throttle body as it appears to be at capacity.
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Joined: May 2009
Posts: 27,505
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From: Yorkshire, England
If cancelling cruise fixes it then seems very likely due to the cruise being activated before - and if you didn't do that then maybe there's a bad switch or more likely bad/chafed wiring.
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Member
Joined: Jul 2012
Posts: 45
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From: Tucson, Az.
I have been reading these posts about unintended acceleration for a while now. It has happened to me in my 2003 XK8, though not full throttle. It feels more like the cruise control is engaged, even though I have not engaged it, just driving in the city. I have had the car accelerate while parking. I have had it accelerate with my foot off the gas. I notice that if I press the cruise control cancel button, the car will stop accelerating and slow down with my foot off the accelerator. Anyone on this forum who suggests that drivers are somehow mistaking the brake and gas pedals, or somehow have such wide feet that they can't help but press both pedals at the same time, are condescending SOB's who should shove their opinions up their throttle bodies with both hands!
My problem with acceleration is not yet solved. It is intermittent. But the fear of driving the car is real. I will try the battery connection solution and see what happens, and report back, if I haven't been canceled from this forum. But please stop suggesting that we don't know how to drive. I have owned a lot of cars over the last 50 years, and this is the only one with which I have experienced this issue. How about trying to help solve the problem instead of insulting the posters.
My problem with acceleration is not yet solved. It is intermittent. But the fear of driving the car is real. I will try the battery connection solution and see what happens, and report back, if I haven't been canceled from this forum. But please stop suggesting that we don't know how to drive. I have owned a lot of cars over the last 50 years, and this is the only one with which I have experienced this issue. How about trying to help solve the problem instead of insulting the posters.
I do agree about those who can't quite believe that most of us know our left foot from our right, and which is the 'go' pedal and which is the 'stop'. My first car was an XK-140 roadster, and I've owned, driven and worked on nearly every model since then, so no lack of experience finding the various brake pedals. If this problem occurs again with my XK-8 or either of my two XJ-Rs, I'll definitely service the battery cables before even opening the hood. A simple voltmeter test of the battery voltage AT THE CABLES showed me the problem, which was verified after removing the cables and testing battery at the terminals.
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From: Raleigh, NC
As a guy who wears size 15 shoes I can verify that it is indeed possible to accidently depress the accelerator pedal and the brake pedal at the same time on my wife's 2006 XK8. I have done this on several occasions over the years. I do not recall ever doing it while driving barefoot, and I have never done it on any other vehicle we have ever owned....
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