The forward alert mechanism randomly turns itself on & off and pressing the fwd alert button does not work. Considered maybe a grounding fault or a dreaded faulty ACC unit. Maybe I just live with the annoying forward alert sound, but fear that it might be a sign of worse to come. Have changed the fwd alert button as a simple thing to try but made no difference. Any ideas ?

Gerry

2005 XKR

 

I have a similar problem. My Forward Alert button light will continue to blink slowly off and on after I have shut the vehicle down. I have posted the problem and have received no response; most likely due to the option of ACC not having been installed in very many vehicles. Or, no one knows what is causing the problem to occur, or they all just hate me.

All aspects operate normally while the car is running, it is just when the car is shut off, the button continues to 'ghost' on me. I think I have brought this problem upon myself. After I purchased my car, I cleaned and lubricated the ignition cylinder, which stopped the blinking Forward Alert light for a time. After shutdown, it would slowly dim away and go off altogether for a few months.

However, while I was in the area under the steering wheel, putting connectors back on their mounting posts and restoring the wires to their correct placement, I decided that I needed to remove the speedometer wood panel and check back there. Nothing looked amiss, but before I reinstalled the panel, I torqued the screws on the gauge cluster for good measure, and re-mounted the panel tightly. After I had done this, the light never went out again.

The panels and the area behind where all the wiring is located are filled with sharp edges and such, so I think I actually caused the wire to be damaged by, and in contact with one of the sharp metal edges of the instrument panel cover by needlessly over torquing. I think this is causing the short that is making the light blink, or it is caught up somewhere else under there. I plan to go and dismantle the instrument panel and kick panel again and see if I can undo what I have done.

 

thanks for the reply - interesting thoughts... at least if it is related to dashboard wiring then it means that its not the expensive ACC unit... I did have the indicator stalk unit replaced a couple of years ago and I am trying to remember when the fwd alert issue started - I certainly didnt have it when I bought the car four years ago. Maybe the two were related and a wire has been trapped during re-assembly. Anyone have a circuit diagram for fwd alert to trace the wires through ?

 

My 2005 XK8 4.2-S Final Series had ACC. I rarely used it but recall even in the early days that the sensor was noted for failure.

Speculating on module, switch or harness fault is guesswork. Substitution of known good parts is one way but there aren't many source vehicles fitted with this option. The only way to troubleshoot systematically is first checking for relevant Bxxxx or Cxxxx error codes but this requires dealer lever diagnostics.

Here is the main schematic in the Electrical Guide:


(double click on the image to enlarge it)

Single pages don't display well on the forum and there are several linked schematics which you will also need. You can download the complete XK8 Electrical Guide - 2003 MY free from my MediaFire account:

http://www.mediafire.com/file/w958mf...e_-_2003MY.pdf

Now back to the question of whether everyone hates 03 XKR .......

Graham

 

I am still not ruling out that it has something to do with my ignition not letting the car go to sleep, as I cleaned and lubed it, and everything worked great.

That was until Summer hit and we got a few days of 100+ degree weather. This cooked the white lithium paste I had used, essentially turning it to clay. I have had the ignition cylinder out of the car a couple of times for a more thorough cleaning, but cannot remove the outer sleeve that holds the 'wafers' and springs in place, to clean them more thoroughly and remove all the hardened lithium; this may ultimately be my problem.

That or the fact the from position '0' to position 'I' on my ignition is barely register-able anymore, my key just turns back and fourth without resistance, like a Fischer Price toy car, no resistance at all, no clicks etc.

 

Never use white lithium grease (or any other liquid or semi-liquid) to lubricate ANY ignition switch. Use graphite powder - that is exactly what graphite powder is designed to do....

 

The indicator stalk; I did notice when I had the cowling off, that the area around the indicator stalk looks to have been re-soldered using heavy gauge 'snippets' of wire. I wonder if they were repairing traces or known breaking points, and got some solder where it should not be that is making unwanted contact. I will have to go check; I replaced the FWD ALRT push button first off which did nothing to stop the blinking led. The crappy thing is, I called the Jaguar Dealer that originally serviced my vehicle and they claim to know what is wrong, but will not tell me.

Another thing I have found very recently is that the driver's side fascia fuse box and surrounding area, is swimming in hydraulic fluid , due to the top latch hoses not being capped off before replacement. I pulled the carpet back from the trans tunnel and the same thing there, hydraulic fluid. I went to the trunk and same thing, a trail of hydraulic fluid from where the hoses where pulled through, uncapped, and fluid spilled out all the way along where the hoses were pulled out.

I need to take the back seat squab off and see what is going on underneath as well since the hoses route beneath. Since I bought the car, the driver's side rear speaker did not work at all, no hiss, nothing. I tried to access the speaker through the grill and surprise, it was already bent to hell as someone else had tried that already. I pulled the top cap and was able to use my flashlight to hold the trim panel away from the speaker box enough to PLUG IT BACK IN, that was the only thing wrong with it, the speakers appear to be brand new. So if the same careful attention was paid to the rest of the wiring then it is a matter of checking for chaffed or unplugged wires, and fluid in the areas the work was performed.

 

Dear gentlemen,

I do know that this is an old thread, but does anyone ever solved the issue?
The ACC system of the XKR 4.2 SC (MY 2003, VIN A33XXX) is working flawless, except of a rare non-functionality every now and then. But I can't disable the forward alert by pushing the button. It stays switched on all the time (red button LED is illuminated constantly). When shutting off the car, the button starts to blink slowly and will even continue to blink when the car is locked or double-locked.
I got no messages in the instrument cluster nor any codes using my SDD. Any ideas where to start digging?

Cheers and regards, Alexander

 

I never never got to the bottom of my problem and sadly ended up selling the car because of another issue

regards

gerry

 

Thank you very much for your reply. Sad to hear that you had to sell your car.

So I'll probably start with a close look to the wirings around the ACC module and the button. Following the electrical guide there isn't supposed to be that much of wiring involved with the ACC module - so let's start there :-)

I'll keep you updated.
Cheers, Alexander

 

Alexander,

You appear to have a considerably more straighforward issue than Gerry as your ACC is permanently ON rather than being INTERMITTENT as he had. The switch looks to be the place to start.

Graham

 

Thanks for chiming in Graham,

you're dead right. Unlike Gerry's my ACC is working perfectly. I do have the same problem like member 03 XKR - the blinking button. I did some research in 03 XKR's posts and noticed, that he got a parasitic drain as well.
Yes, TSB 414-S840 has already been performed to my car and I doublechecked the presence of the diode kit. I also turned off the auto headlamp feature which didn't change the drain whatsoever.

My first thoughts had been targeted at the switch too and I'll check it for sure.
But on the other hand I doubt to find anything around there. I'm afraid I might have a bad ACC module, as the ACC switch appears to be more likely a button than a classic switch (which engages (closed circuit) and disengages (open circuit)). According to the electrical guide the operation of the ACC button closes a circuit from ground to the ACC module PIN LF61-12 for the time the button is pressed. But the ON-OFF-state of the ACC feature seems to be controlled by the module itself.

Let's see what the close examination of the wiring involved will reveal ;-)

Cheers, Alexander

 

Hi Alex,

Let me try and revive the thread like you did. Did you manage to get to the bottom of this? I had my car in the garage yesterday for a fuel filter replacement and some other minor work. All was fine when I drove off, on the motorway suddenly the forward alert started cycling through on/off... dashboard lights dimmed/brightened up and the headlights kind of tremored. Quite scary since in rush hour I thought it would go powerless.
Garage confirmed they had not done anything with the battery... I did put the car on a charger overnight.. All looked better but my forward alert has the following challenges:

• the forward alert button / switch is not lid like the valet button next to it.
• forward alert either is off, quickly goes on/off like a drumbeat
• using acc... all is fine.
• at a point it worked for about 10min as it should (ie the buttons to select the forward gap even)
• pressing the button sometimes triggers a minor little red light behind the button.. but leads to the cycling again.

This is a 2004 XK8, 43000 miles only the car had a replacement (reconditioned) one fitted by the previous owner in Sept. 2020.

 

To make sure that the topic is not left unfinished, and in case someone else is dealing with the same problem, here is the end of the story.

I knew the problem must be in the CAN bus, so I used the schematic to find all the connectors where the bus leads and measured to see if the resistance was 120R both ways. I also measured the resistance to ground and power.

I disconnected the various units on the bus because some of the units could be interfering with the other units communication and did tests.

I ran a Network Integrity Test in the SDD with the result that the bus was fine.

Again, I became suspicious of the BCM because some units were not active on the bus. After testing with other BCMs, I found that the problem was not the power supply to the units, but that it was again a bus fault.

Since the instrument cluster is a bus gateway, I bought a used instrument cluster. After replacement, the car started to communicate..

The minor problem was with removing the keys from the malfunctioning clusters and replacing the new ones. One day of trying and finally everything worked. Everything works, only now the car has 100.000km less mileage. But without a PIN, it can't be changed...