Help!! I think I locked down my XK8 inadvertently. Since I only received 1 key with the car when I bought it, the Valet key, I used the transponder to lock the car today. When I came out to place items in the trunk I forgot to unlock the car first, tried to open the trunk first, and of course could not. Then I used the transponder to unlock the car, open the trunk. When I went to start the car, everything came on EXCEPT the starter!!.
I think I remember reading somewhere that it is in the passive starter lockout???? I called friendly neighborhood mechanic who sort of agreed with me. Suggested I find anther way home. He said he would check the car see if it would reset. Later said that it went into "Limp home" mode, and would 'maybe' get better?
Is there a way to recover/bypass?
I know, I need to get the primary key. Plan to go to Jag dealer soon.
Any suggestion??

 

Sam when are you going to take the hints your car keeps giving you and get a new battery?

The other day your top and windows act up. Now this. Your battery may seem strong. But its not what your car wants and needs.

You can get an AGM battery at Advance Auto for about $150 if you buy it online with 20% off code and pick it up at store.

It will seem like a different car with the proper juice. We have all been where you seem to be now.

 

You really should also get another key and in the meantime it's possible to convert the valet key to a "real" key

 

I have had the battery checked after I purchased the car as part of my post purchase check. It is almost new. I do plan to get a Primary key from the dealer, or if thst is not possible, convert the valet key.
Is there a way to bypass the passive lock down if that is in fact what happened??

 

Both the green and black key have a security chip built-in. This setup is meant to prevent hot wiring, like in the movies (reaching behind the key lock and manually connecting wires). Your problem is elsewhere, most likely.

First, wiggle the shifter from P to N a few times. There are switches in there that age like everything else. Also, try and start the car in Neutral.

 

My local mechanic picked up the car after it sat for a couple of hours(I had to go to a meeting). It had gone into reduced perf. mode. He checked the OBDII and found that it had set 2 codes. One for an engine ECM and one for transmission problem(I had the codes, but not this morning as I write this tome). Once reset, the car ran fine. He checked it over, no problems for the rest of the day. I picked it up the next day, drove it for 3 days like a dream, locked and unlocked the doors, no problem.
Last night, went to dinner, left the car in parking lot while I took my wife to dinner, when I came back went to get into the car and it was locked down again. Same problem. All lights, No Starter! The parking lot was at a private club, well lit, so I doubt anyone had tried to open it the short time I was gone.
I left it over nite, this morning I went back, started it, drove it home in reduced performance mode. Will take to mechanic Monday to have him again check codes to see if same codes are set.
Why would unlocking door cause car to lock Down? Anyone with any ideas???? As I said earlier. Battery checked perfectly good.

 

What voltage is your battery reading with the ignition off?

 

I don't know what the voltage. My mechanic who works everything from '53 Chev. to 2019 MB's and BMWs has checked it both with and without load, and says it is a good battery, so I am confident that it is good. He sells batteries, so he could make money on me if that were a consideration.
Today I took the car to his shop to have it checked Monday morning. It started with no hesitation. Yellow engine lite(Check engine lite?) was on, but no other warning lites were showing. Nothing indicating 'Limited Performance'. It accelerated normally up to 50 mph as I drove it thru local streets.
My mechanic will check for codes on Monday to see if the same codes were set (Engine ECM and Transmission). Don't know if this would be the cause off a security lock down, but it does not seem to be logical.

 

Sam, good luck with it. Hope it turns out to be simple solution for you. Let us know what happens, this is a good one.

John

 

We will be working it this week. After the mech. checks the codes, I will be taking it back to the dealer to hopefully have the problems cleared. Now I will see just how respectable this "Used Car dealer" really is. It came with a 50/50 limited warranty. Just how 'limited'?
Right now, I just want to get the problem cleared and get on with the use/enjoyment of my car.

 

And the saga continues.......
I went to my local Jaguar dealer for a Master key. After waiting a week, and paying $401, I was handed a GREEN headed Key, just like the one I had. I explained that I had a valet key and wanted a Black headed master key. The parts and service manager proceeded to explain that the key that I had and that they had supplied me with were the correct master keys. When I tried them on the boot/trunk and glove box, they opened both. I currently do not have the keys with me, so I cannot look at the ends to see how they compare.
As to the shut down, I still have not gotten a solution. No one has discovered what or why. The car goes back to the selling dealer on Friday for a code check. It has Locked me out twice now. In both cases after sitting for 2-3 days, it 'Reset' and could be driven off as if nothing had happened.
The lock down would not allow the key to turn past the start position, the shift lever could not come out of 'park', starter would not engage. All lights, gauges, radio, etc came on normally. Everything acted as if the neutral safety switch was not engaged. Pressing the 'Lock'/'Unlock' buttons on the transponder had no effect.
I have been driving it now for 2 days with everything acting normally. The last time everything was going great, then I parked in my drive, got out to get something in my garage, got back in the car, and tried to start the car. Nothing from the starter...... Sat for 2 days, then all was fine.

 

Have you tried to start the car with the shifter in Neutral? You should be able to get the car out of Park by pressing on the brake pedal. The brake switch tells the computer to release the interlock and let you shift out of Park. If that does not work, repeatedly press the brake pedal to try and make this brake switch work (switches frequently fail "sometimes", rarely outright). That brake switch is a known weak part, and will have to be replaced if you cannot get out of Park. To continue the test, remove the plastic plug on the shifter surround and bypass the interlock with a key or screwdriver. Once in Neutral, try and start the car again. There are several switches around the shifter. Try and move the shifter back and forth a few times to see if the switches can be made to cooperate. This should all be done with the key one position short of start because all the computers have to be powered on for all this logic to apply.

Best of luck, keep us posted.

PS: If you need more assistance with the key the dealer provided, DON'T post a picture without blurring the cut section...

 

Thx for all the info. It appears I do have 2 master keys with the proper indents on the end.. The head is in fact black, it just is faded badly. As for shifting, the last time I was locked out, the shifter would not move from park, no matter what I tried. I used the brake, key position, everything, and nothing would let the shift lever move. Previously, the lever had moved into other positions, but the starter would still not turn over.
Again, the codes set were #1637, !643, & 1000. After sitting for 2 days, the car 'reset' and has been driving normally. At first it drove in 'reduced performance' mode, and then normally. I don't know if this is an ECM problem not.

 

Sam, there's a lot of sage advice from many and you could have a combination of issues. Our XK8s are getting on and even if your battery seems new and fine, it probably runs down when in use, as the dreaded "stray current" and/or a weak alternator probably means it's not getting above 12.5V even after a good drive. These cars were top of the line when they were first produced, but father time gets to everything. Keep an eye on the battery gauge before, during and after driving. If you're confident this is the problem, go through checking voltage differences between the grounding points.

Your starting issue could be linked to the brake switch as previously suggested, but mine starts without having to step on the brake. Maybe you have an intermittent problem moving the gear level from Park. Most probably, there's either a security issue, where your key is not recognised (does the engine crank?) or the transmission doesn't recognise it's in Park (old switches in the J-Gate Module). Some suggested to try and start in Neutral.

There's always the Hard Reset (take battery cables off and touch together) to try.

Let us know how you get on, but I suggest to tackle each problem separately.

 

Sam
FYI #1000 is simply that the diagnostics hasn't run 2 cycles - Just try the car more!
#1643 is the fuel pump monitoring system - When you start the car, can you hear burbling from the fuel tank behind the rear seats?
#1637 is the CAN linking ECM/ABS circuits - Network malfunction - Do you have a ABS warning on the dash? Clean ABS sensors

 

It looks like there is a problem with the CAN network. CAN is a high speed data bus that links the more important control modules, like the Engine control, transmission control and ABS. For example, the TCM knows the road speed by getting that information from the ABS module, same for the speedometer.

You will need to find out the cause of this and fix it. The electrical manual describes all the control modules on CAN. It includes the instrument cluster and the shifter lights module. If any of those modules fails, it can crash the bus and prevent these (expected) messages to go through and give you these codes. Could also be the CAN wires being pinched somewhere. You might have to reach out and find out what repairs were done recently, or try and get some clues as to what could have happened (like dumping a drink on the shifter from the wobbly cup holder). Does your car come with the radar cruise control? Check the ECU bin drains correctly when it rains. Also, there is a plug on the transmission that leaks sometimes and could cause CAN errors.

Best of luck.