Hi new XK8 4.0 1998 convertible owner near Ormskirk in the UK. ( Oh she has a duel fuel LPG conversion too)

Starting to find some errors and issues with my car and wanted some advice...

After driving for about 20 mins the Amber warning light and engine failsafe mode come up on the dashboard. This has happened for the last few days but had not for the weeks I had owned her before... a coupe of times while on the motorway obviously just doing 70MPH and didn't really affect the performance..

A couple of time driving locally and again didn't affect performance in fact tested her in sport mode and revved freely and fast so utterly confused as to what it is supposed to be telling me

No other warnings coming up, no check engine or lights..

I have scoured Google and the forums and can't find an answer to this problem so need your help please...

To add for diagnosis sake..

The cruise control works prior to the Amber light and engine failsafe warning coming on, when they ome on cruise control stops working...

The remote key fob has stopped working i have cleaned it thoroughly and changed the batteries but nothing..

Any help would be greatly appreciated I am hoping to do a few long trips this week abd wanted to use her but am nervous as I don't want to do any unnecessary damage

Looking forward to your thoughts.. thanks Daniel

 

Daniel, this is quite a coincidence. Read my response to the post directly above this one titled loss of vacuum. The gent has 1951 in his name. This is exactly what happens when your vacuum hose comes off the throttle body port. There's a photo in my response. Hope this solves it for you.

BTW if it does. Check your motor mounts. Just ask if you need directions.

John

 

John,

Here's the link to the thread you mentioned:
https://www.jaguarforums.com/forum/x...cruise-244253/

Threads don't stay in the same order. They continually re-arrange in descending order from the one with the latest post.

Graham

 

Thank you Graham! I should have known.

John

 

Do you have any DTCs you can share?

 

Hi thanks for the advice, I looked at the thread you mentioned and your photo and my throttle body looked to have the hose tightly connected so not sure whether I am missing something with this fix...

Should I be tracing the hose back to where it started or taking it off and seeing if it has a hole or leak somewhere..

I took her out for a 180 mile trip today, which I am happily amused to say she does on £15 of LPG !!..

Sadly the failsafe light comes on 10 mins after starting her up ....pretty much always happens now but doesn't seem to affect the performance

I purchased a OBD 2 Bluetooth adapter and the Torque Pro app and ran diagnostic tests and no faul codes come up even when driving and the Amber light is on with the failsafe warning.. stressing me that something is still wrong..

Sorry showing my ignorance now....What are DTC,s.??

I did put on my profile signature the fact she is a 1998 XK8 4.0 UK spec with a duel fuel LPG conversion is that what you mean..? If not let me know I am sure I will catch up with the lingo as time moves on..

I will hunt through more threads and see if I can find any other ideas but would appreciate any ideas and guides for a fix...

Thanks again Daniel

 

l had this same thing happen to me.

For me it turned out to be the brake switch needed lube (or replace)

l also read that it can be something to do with the fuel breather system found under the LHS front fender cover. Apologies for lack of detail, i was many fixes ago

 

DTC = Diagnostic Trouble Code. Also known as OBDII codes....

Code P1111 is OBDII nirvana. When your scanner shows this code and nothing else, all OBDII systems are performing as designed and all onboard readiness monitors are clear and ready for the various mandatory state emissions inspections....

 

Honestly, I can't remember the exact message that came up in the display - but I know it said sumpthing,,,

I just noticed you had a convertible.

What happened was I was driving and was about to get in the highway. The car was in drive, I had the top down, and I hit the switch to put the top up. I can't remember if it was a "FAILSAFE" message or some other but the car didn't like it. Until I stopped, ran the top up and down thru full cycles, the messages stayed. Turned off the car and started it again and the message was gone.

For your issue I would make sure the car is in P or N and run the hood up and down thru a cycle - can't hurt. I know the message is a royal pain.

If not this, you might just want to try disconnecting the battery for a few minutes (not a full reset) and reconnecting...?

Yeah, as mentioned, DTCs are CODES... Lol, the letters and numbers that dance around, keeping us up at night, like poor ol Charlie Brown...

 

Morning ....thank you for the ideas I will get onto the brake switch clean fix and the hood cycle fix and report back later today...

As mentioned ibhave run diagnostic OBD2 tests with Torque Pro and another UK recommended app when had been parked up and also while running and they are showing no fault codes which is really confusing..

One question on these OBD readers
live shows rpm pretty accurately
It's showing ridiculous low horse power figures and from actual driving sensations they must be wrong so wonderijg how accurate these things really are??

Will keep you updated on these fixes later today...thanks again Daniel

 

lf its the brake switch you will get no code, just the amber light and failsafe warning. Also, the cruise will not work (this is also tied into the brake switch.)

 

Hi I tried to spray the brake switch with WD40 this morning and did the roof cycles as also suggested and then took her out for a run and the same things happened

Failsafe mode and Amber light..

I went to a local Jaguar repair shop and he had no idea said he had never heard of failsafe warning and no codes..my instinct based on reading the threads and forums is the brake switch as a couple of you have suggested so next is the how to do it...

Now I am not a big fella by any means and I struggled to contort myself under the dash by the pedals to spray WD40 randomly in the vicinity.... so any advice as to how to get to the switch and would you try and clean it, do a test on it or buy a replacement (hoping there is a non Jaguar part that fits for a fraction of the cost)??

As always any ideas appreciated and I will try to follow ..

I will take photos of the LPG system and post as per an earlier requests,

Thanks for all the help.. D

 

I very recently responded to another member regarding the brake switch. I am by no means small (74") and 80 yrs old, and can still access the switch. Disconnect the switch and check the continuity across the outer pins. If the circuit is open the switch is defective.

You do not need to remove the whole switch mount from the car, just loosen the upper 8 mm nut and remove the lower one then work the switch out with a little bending. The two micro switches inside are for the cruise control and brake lights. I don't recall the source and part number off hand, but if your switch is faulty I or another member will provide the info and you or a electronics a shop can repair at a fraction of the cost of a new switch.

 

Maybe these abnormal symptoms might be related to the fact that your car is not the usual set up, and it is related to the LPG dual-fuel conversion?

 

.....................a dealer talking out his ****, well, thats never happened before, was the guy you spoke to actually out of short trousers when these came out.......... Hopefully few grand in the dealership for no result is a lesson you dont need to learn.

 

Hi guys family visits and house hunting kept me away..

Thank you for all the advice I beleive it will be the brake switch many of you suggest... will find a way to get it out if anyone can recommend a replacement at a sensible price..

I don't think it's related to the LPG it happens when running on unleaded also and goes out as soon as turn off the car then back on after a few mins and doing some braking...

Running OBD with Torque app constantly never see any errors... its just there to make sure I am on edge I guess..

Agreed the JAG dealer surprised me when he said he had never heard of this problem and he must have been in his 60s so no kid.. probably just smelling the potential cash pit on a newbie..

So thank you all for for advice you have given so far and the advise I will need moving forward.. I will be honest and tell you all that I read up about JAG ownership before I bought the car and one thread that is consistent and true is its well know the JAG community is special..

So a big Friday cheers to you all... Dan

 

Dan I had the same problem, fail safe and amber light and no OBD codes. It started when I attempted to engage the cruise control. I have a 1998 XK8 and after a battery reset the problem went away. Now I don't engage cruise control and will see if the problem returns.