Well hello, stumped here in So FL and hoping someone on the forum may have some insight. Battery good at 12.8v, but no start situation, just fault lights and fault audible which starts with EBS, ABS, Tire Pressure System Fault and cycles through every system fault to the last, which says " Cannot Apply Park Brake". I'm confident the battery is good and it has a battery tender when not in use. I have to disconnect the battery to stop the fault warnings, visual and audio. Turning off power and locking the vehicle does not stop the fault warning. Have tried:

Removed battery cables, held together for 1 minute
Left cables removed from battery overnight
Stomped on brake peddle hoping that connection might be the issue
Tried releasing and applying the EBS varying combinations with start/stop button
Moved gear shifter through pattern and back to park
Checked brake fluid level
Various curse words

Thank you in advance for any insight provided. Chas.

 

Bad earth?

 

The battery is not good and the symptoms you cite are perfect examples of the symptoms caused by a faulty/ low battery in these cars. The various modules need full battery voltage all the time. If they don't get it, they behave as you have described. How old is the battery? More than 4 years old? Even using a battery tender will not do anything more than mask a failing battery for a while. There are many, many threads on this issue.

 

Hi try with cables than other car battery to see.
Have you good battery in the key ?

 

Gregory, I just ordered an Interstate AGM battery this morning and should have it to install Monday. https://www.interstatebatteries.com/products/mtx-49/h8 The existing AC Delco battery was dated Jan 17 and installed by the dealer that month, so possibly it has gone bad. I tried jump starting with a second vehicle this am before removing the existing battery, same system faults and no start result. Thank you for your input and will post an update with new battery installed early next week.
p.s. my wife is Canadian, from a little town called Amherstburg, Ontario.

 

Hi Marc I did try jumping the battery with a second vehicle and will check the key fobs as you suggest. Thank you.

 

Well you have another battery coming so time will tell but just know Jaguar recommends you do not use another car to attempt a jump start your car. It can destroy the harness if memory serves. 12.8 volts resting is strong. You can have someone attempt to start the car with the volt meter attached. If the load drops below 9.7 volts, battery is toast. please let us know the outcome Monday.

 

System Faults
Installed the new battery after keeping on charge all day and still the same systems fault messages and fault audio. The only way I can get the fault msg and audio to stop is by disconnecting the battery? After the fault message cycles through all faults it ends with " cannot apply park brake". Hoping we can find a fix on the forum
otherwise I have a 2 hour tow to the Jag dealer.

 

Edit: still won't start? Not clear if this is your only fault left or it still won't start.

 

Hi Sean, yes same issue, with the start button and brake applied all system initially seem normal with lights and chimes, but then the fault warning starts and cycles through what seems to be every vital component in the car and wont permit the engine to crank and start. I do not have the testing tool you highlighted. Thanks.

 

Thx Chasr. Short of having it towed or having Amazon send you a diagnostic tool to retrieve codes, you almost relegated to following PerterV8's bad ground guess. What your experiencing is all the signs of a bad battery and you clearly went through the steps. Sorry not any help.

 

OK. You're probably at your wits end. And there are a lot of folks suggesting valid ideas that do not help.

So, time to cheat the computer. Find the inertia switch-sensor. Mine is inside my driver's door jam (2001 XKR). This little device enables some of the relays and disables others. Follow the wiring diagram. Short out the terminals. When you turn the key to position I (dashboard, but do not crank), only a few lights should illuminate. Take a picture with your iPhone (or equivalent). Send it to me with a private message.


I'll try to attach the electrical diagram wiring diagram for my car. Your will be different, but not much. Download the wiring diagram book for your car ... it's somewhere on the Jaguar Forums web site. What your are trying to do is figure out where the power to the starter motor is blocked. Odds are the computer thinks something is set or not set, and then everything fails. All you need is an ohmmeter and a voltmeter. Take your time. Think of the satisfaction when you fix it yourself and don't have to tow it to the dealer, who probably is 100 miles away.

Keep me posted. I only as far away as Tampa.

Very respectfully, Bob G.

 

Thank you Bob. I just went out to take a quick look but could not locate this rascal. I will try again tomorrow and get tack to you.

 

Good morning Bob. Found this service guide posted by Sticky. I've looked for the Inertia switch in this guide but so far I've not found. Any chance you could take a look to see if you can identify this switch? You're right, it is a 2 hour tow to the Jag dealer from down here in the FL Keys, so with help possibly this can be resolved here at home and I can learn along the way. Thank you.

 

Good morning Chasr.

Here's a picture of the inertia switch. Yours might have a red or black top. It just peels off. Anyway, the only purpose of finding the inertia switch is to gain easy access to the connector pins. On my '01 XKR, it is located inside the driver's side, left of dashboard panel. The panel is triangular shaped, and jump pops off. The switch is inside. It's only purpose is to cut off fuel in case of a roll over. When that happens, several electrical relays are turned off (de-energized). That's how the power to the fuel pump is cut off. Anyway, something is telling your car that one of the computer pins is either open, shorted, +12V, or otherwise not in the correct mode to allow starting. If you can find the similar electrical diagram for your car (and it will look exactly like the one I provided), it will show you the wire colors. This is what you need. You will use an ohmmeter and voltmeter to see which wire is not in the proper mode and is keeping you from starting your car. It will also allow you to easily check grounds, voltages, etc.

I know it's frustrating when the car won't start, and all obvious things are verified, but then it is almost always something to do with thew computer. Mine was a wire that was grounded, telling the computer 0V, instead of open. Took me months to figure it out. Cost: $3.

Keep looking, Best regards, Bob G.

 

Hi Chasr. I opened your electrical guide. Start with page 38 of 118. The problem is something like a short or ground that keeps the starter motor from engaging. Not to sound like a jerk, but did you do anything electrical to the car lately? Did you have it at a local garage? Have you or anyone else installed or removed any accessory? Have you tried the gear shift, making sure it is in park or neutral? It's a long list, but it's simple. Just think of these simple tests as free, compared to paying the Jaguar dealer $200/hour to do the same thing.

What you are looking for it anything that seems wrong. With the electrical diagram in hand, and basic understanding, you can see what should be open or closed, +12V or ground, depending on the ignition switch position. With patience and perseverance, you'll find the culprit. Just keep trying. Remember, on Jaguars, most everything is wired +12V, and switches and relays close the ground side. You'll need a simple trouble light. It's like a fat screwdriver. One wire you clip to a ground point. The point of the trouble light pokes at other things. When you touch +2V, it lights. Won't short anything, or hurt anything. You can get one at Home Depot, WalMart, or any auto store. Mine was $4.

Best regards, Bob G.

 

Sorry about my typos. The "1" key on my laptop sometimes fails. So +2V about meant +12V.

 

Bob, nothing has changed with the vehicle config, BUT there was one event that may play a role here. About a week ago a transformer blew in our neighborhood. The power was out for half the day. It was just a few days later I went to drive the XK, I unplugged the C-Teck charger and then when I opened the cars rear trunk to place the charging cord in the truck compartment, with key fob in hand, the anti-theft security alarm activated? I found this very strange. Used the key fob to disarm the alarm. Then when I went to start the car, this whole fault warning resulting in a no start situation began. This happened (Anti-theft alarm activating) to me once before with the XK after a dead battery situation was rectified a couple of years ago. Possibly the issue is the result of this transformer and a related power surge via the c-tech charger? I have the test light and will start poking around tonight after work, although this is all french to me. Thank you. Chasr

 

Hello Chasr.

Well that's a lot of information.

Suggest BEFORE you poke anything with the test light, you might want to try to reset the security system.

Consider researching how to do this on Jaguar Forums, or the internet.

To me, it seems like whatever triggered the security fault, and whatever you tried to disable the fault, might have been incomplete.

Once the security system triggers, the car is disabled to keep any unwanted person from starting-stealing your car. That also means the start function is inhibited.

So, at a minimum, try to enable the security system, then disable it. Try locking the car, then try opening it illegally, perhaps through the trunk release lever.

I am unsure what you need to do, but it seems like it should be a lot simpler than looking for a short or ground.

Let me know what you learn, and whether it works for you.

Best regards, Bob G.

 

New info indeed. Start by pulling the gauge cluster logic fuse. In the central Junction Box, Fuse F5. Also F28 in the engine Bay which is power to the gauge panel I think. Pull em, check them and leave them out for a minute.