Hi,

In the past, the rear side lights would blink when I opened and closed my X300 Jaguar Executive XJ (1997) using the key.

However, since the cold winter, there have been some battery issues. Now it seems that because of this, both the side lights no longer signal when opening/closing the car. The starter motor also no longer receives an electric signal to start, and the gear shift is now stuck in 'P'. Additionally, the central locking system is not working anymore.

I have since charged the battery and also tried a different battery. But this does not seem to solve the issue.

Does anyone have advice on what next step I can take?

 

Welcome to the forums Loweherz,

I've moved your question from General Tech Help to X300 forum. Members here with the same model will be able to help.

Graham

 

The gear shift lock solenoid is controlled by the body processor module which gets a command from the brake switch

The brake switch is 2 switches in 1 package



There is a TSB to upgrade the switch

The starter motor is enabled by the body processor module . it is the heart of the starter circuit

Never install the battery backwards .........................................ask me how I know , recoverable by yourself / fuses

The central item between the 3 issues is the BT - 4 connector above the fuel tank , you can look to see if the tie - wrap is on the connector lock over bar but do not remove connector yet

 

Thank you Parker, yes, I'm pretty sure the battery has been installed backwards. I'm new on this subject, have not replaced batteries before and am learning mainly by experimenting and making mistakes, including simple ones.

I checked the below fuses;

Engine compartment left side ; fuse no. F3 start relay 25w

Engine compartment right
f6 engine management system relay ECM 5w
f11 engine management system relay supply injectors 20w
f12 engine management system start relay, ignition, air pump, fuel injector relay 10w

Rear compartment right heelboard;
F1 central door lock 15w

Luggage fuse box
f5 Body Processor Module (BPM) control module

They all seem ok.

To check the BT 4 connector above the fuel tank I probably would need to lift the car, is that correct? (the Jaguar's parked in front of my home, I cannot move the car with the gear shift stuck).

Please advice.

 

I put my battery in backwards ............... twice

So I'm not new to the subject

You can place a tape on the battery with a big arrow pointing fwd

This I what I found ....................................

 

Never clamp the battery fwd positive post too tight , breaks / splits the special nut underneath




It will ( battery backwards ) blow some fuses , so need to check all of them against page 21 first

Keep track of which fuses blow , and then restate your new symptoms.as some are resolved

Best to focus on starting first , define if you get starter rotation or not

If you see 300 RPM on starter rotation , if no tach indication the crankshaft position sensor will read 1300 ohms as a basic meter reading

You can read it from the Engine ECU connector , Black 23 and Black 26




The # 1 fuse is closest to the fuse box positive terminal post

X300 1996 LWB.pdf (jagrepair.com)

And this TSB

15-16 Fuses – Ratings_Circuits.pdf (jagrepair.com)

 

I put some editing in above post

 

Going back to your original posting, my car had the identical symptoms with the electric locking unresponsive to both the key fob and the inside dash button, and no response from the starter when you turn the key. Plus the alarm system would go off at odd times.

In my case the problem was a failed security module, relatively easy to find and replace, located in the trunk against the inside of the fender, above and left of the fuel tank. Replaced with a used unit and all was well.

 

Thank you, that might be the issue indeed. Would you have some more detail on the security module (type/what to look for)?

 

You have to pull the left side trunk lining and then peer up and to the left against the inside of the fender below the gas filler hose. It's a flat metal box held in a bracket by two studs and there's a wiring strip connector on the back edge, once you see it you'll know as it's the only thing up there. It's clearly marked with a part number on the face, mine was LNA-2600-CC-009. My used one cost $500. I think you have to reprogram your key fob to match it.

 

Issue solved!

I disassembled the Security ECU programmable part (that seems the European naming), by the looks of it it was not damaged.

AJaguar mechanic mentioned the x300 electricity can be dodgy and adviced to just take out the Security ECU programmable part, detach the battery as well as the 2 batteries from the remote (the other remote's not working), and try again.

And it seems this did the trick. The central locking's working again, the remote's working, both (tibbe) keys work, the lights flash if the car's open and the car runs like it did before., good times!

One helpful video to find the Security ECU programmable part was this one; Programming the keys myself was not possible due to the valet button not working/allowing to put the Security ECU programmable part into 'learn' mode. I couldn't find people in the area that had the jaguar ID software to read the computer via the OBD port (not even the Jaguar dealer had the pre2004 system). But that might be an idea as well for those running into the same issue. This is a useful post for those with the same issue; https://www.jaguarforums.com/forum/x...-module-33600/ as well as this one https://www.jaguarforums.com/forum/x...solved-237910/ and this Jaguar XJ6; Jaguar X300; not starting; start

Next to replacing the Security ECU programmable part I would've considered replacing the Key Transponder Module (KTM). As I understood it, the KTM is the anti-theft system whereas the Security ECU programmable part is more to have the remotes communicating with the electricity system which then allows the transponder chips in the Tibbe keys to communicate with the KTM and turn the key. But I did not dive into KTM further, only have hints of how this probably works.

Anycase. Thank you for the help. Much appreciated.

 

Ok, issue's turning up again.

Though the central locking worked, after a few months I couldn't start the engine anymore. After disassembling / reassembling the Security ECU + car battery a few times also the central locking stopped working.

So I bought a new remote, but that didn't do the trick. Then I replaced the Security ECU, but again without avail. Finally a Jaguar mechanic suggested to replace the Body Processing Module (BPM). That didn't work with the 'new' Security ECU, however once we replaced the Security ECU with the old one all remotes worked and the engine worked again.

I concluded that the old Security ECU clearly is programmed with the original keys (a replacement Security ECU would need reprogramming then, see also earlier posted video here). Also the Security ECU and central locking are clearly related. As seem the Security ECU and communication with the start engine via the BPM.

Today I did a small tour and left the car (unlocked) on the driveway. Upon wanting to drive a few hours later, again the central locking failed with all remotes.

So again it seems I need to turn back to the Security ECU.

Nb reprogramming the keys using the valet button has not worked so far. And tomorrow I'll ask the Jaguar mechanic to drop by with the jaguar ID software to read the computer via the OBD.

Could I ask your advice?

It seems to hinge on this Security ECU given its the central locking system that doesn't work (which is a task between Security ECU & remote).
Any antenna that I should check?
(cables should work fine right? could be cables that are plugged in the Security ECU ofcourse; I'll recheck tomorrow)
The Key Transponder Module (KTM) doesn't seem logical as (though its the anti-theft system?), the remotes are not connecting to the car which points to the Security ECU.
Other?

Thank you for the help. Much appreciated.

 

You probably have the chip in key with a transceiver / exciter ring on the key barrel with a decoder around the center of the dash

The decoder get's it's power through the large 48 pin connector ( BT4 ) above the fuel tank with pin 14 ( Brown / Blue )

Do you have a tie wrap on that connector , don't remove the connector yet as hard to reconnect

The decoder get's it's power with trunk fuse # 4

In the very end if a chip in key immunization issue Andy can delete that item in the Engine ECU ( BPM needs an enable from the engine ECU for starter rotation )

There are 2 types of remote rear window antennas mixed around by mistake on production , one for 315 hz and one for 433 hz

 

Your reader / exciter control module ( in the dash ) and coil for chip in key immobilization ( security ) is on page 150 for your 1997

Power source 99 square is fuse # 4 trunk reference page 34

notice on page 34 the Brown / Blue color wire passes through the BT4 connector position 14

This fuse # 4 is hot at all times and does not require the relay in the corner of the fuse box to close , needed for fuse 10 , 12 , 14 , 16 for all fuse boxes

jagxj1997.pdf (jagrepair.com)

See page 42 for a 4.0 liter engine , yours may be a 3.2 liter

The reader / exciter control module may be referred to as the decoder which has a wire to the BPM for starter enable

Somewhere along the line the schematics are not perfect / complete , the chip in key immobilization has stumped many , but US models do not have chip in key

 

Thank you Parker.

Yes, its a European car, so maybe the key barrel ring + decoder are an issue, I'll check the powerline and the brown/blue pin connector. I'll double check the fuses (trunk fuse #4) as well as the rear window antennas. Problem here is the diagnoses software couldn't find the issue either. But I'll double the reader/exciter module as well.

You mention 'Andy can delete that item'; could you clarify please what Andy's does (so I can replicate?) please?

Thank you for sharing the link, it doesn't work (in the past I had the same issue, are there any other links)?

The reader / exciter control module may be referred to as the decoder which has a wire to the BPM for starter enable

 

Andy ( in England as an original Jaguar company X300 designer / engineer ) is way ahead of me as to his delete of the immobilization system , someone may have his communication link

The link for the wiring schematics is in the top of the first page of the X300 section as ' stickeys links "

I saw some work on Youtube or somewhere of someone making a device that can test the RF signal as the final test ( after decoder / module ( sometimes referred to as a transponder ) power at the power pin is about all you can do ) of an outputting / functioning key barrel coil / module

Maybe a test lamp ( to not see the current available / lamp brightness waver ) on BT4 connector ( as fully installed ) connector wiggle

Fortunately, the chip in key technology ( as a whole between different car manufacturer's ) frequency is the same abouts

Keep asking questions to expand on a knowledge base for me as well as others

 

Andy Stoddart's username on the forum is XJREngineer.
His email is andystodart4@gmail.com.

 

Ok, thank you Parker 7 and V126man, I've sent a private message & email to Andy asking if a can work around the immobilizer system in the ECU.

The powerline, brown/blue pin connector, trunk fuse #4 and rear window antennas seem fine. Meanwhile I ordered a reader/exciter module as well as a mod / transponder key ring to see if changing these will work.

Funnily enough in trying the 'reprogramming key' sequence (with open driver's door, click trunk open button, 5 x vallet button, then click remote, again vallet button, another remote) the keys were recognized and I could start the car.

However upon walking into / out of the house the keys didn't work anymore. Also the reprogramming key sequence couldn't kick off as the 'trunk button' wouldn't work.

That either makes sense (exciter/starter module / mod transponder key ring) or offers new challenges (still a problem in the security ECU though I hoped that problem could be discounted after the mechanic changed the BPM and couldn't get the keys working with the older security ECU but could get things working with the old security ECU). I've sprayed some wd40 on the locking mechanism in the trunk where I also found this piece of metal floating around;


If I connect the 'new' ECU that I recently bought, one remote allows the central locking module to work (the other two do not work). Also the 'check engine' light is off and I cannot start the car. This time however the button to open the trunk works (which it doesn't do with the 'old' ECU). However the reprogramming sequence doesn't allow me to program any of the keys (which as I understood it reprograms the EEPROM 93c46 chip on the security ECU: I'll research where to find this chip on the previous ECU and transfer it to the new ECU as well).

Ok, back to work.

 

Pic , some sort of 8 pin DIN connector in a stereo system ?

DIN is not used in the factory security system , just the premium factory stereo

For a fully functional security system is in this video , but the car's interior chirp's speaker may not be working as a matter of the speaker alone and not the system

 

The new ECU with the EEPROM chip from the old ECU allows the 3 remotes and the 2 keys to fully work and start the engine.

I made a drive yesterday afternoon and checked if things were still working yesterday evening, this morning. This as previously (with the old ECU still in use) the communication through the remote/key with the car was unreliable (see previous posts).

Ok, things are looking up so far. Lets see what happens if I don't touch the car for a few days/weeks. So far so good.