Jaguar xj6 x 300 3,2 litre 1997.

My Jaguar does not start nor crank the engine when I turn the key. The lights go on quite well, but there is no life in it. I have changed the body processor unit with a used one, as I got a hint about this on youtube but still no change. The remote will not work (new battery installed) .

Does anyone have a solution to this problem?

Regards
Ivar
Norway

 

With your swapping of the BPM where you able to verify if the specific starter relay clicks with your fingrt on it.

There is a large 48 pin connector above the fuel tank that contains the wires between the SLCU and the engine ECU which has a inhibit wire ..The connector can migrate loose and be careful not to break the overcenter locking pins

The green fuse # 4 in the trunk powers the SLCU

Below 11.4 volts the engine will turn over but not enough voltage for the ECU

 

Dear Lady Penelope

Thank you for your prompt answer. I have not been able to check out the car before today. A heavy gale sent trees falling all around my cat, and it needs to find shelter soon, as it now rests outside...

I checked out your tips with the following results:

1) The starter relay does not click.
2) The 48 pin connector in the boot is untouched. I opened it and sprayed it with some electronic cleanser.
3) All fuses in the car have been checked and are ok.
4) the battery is at 12.48 volts.

Still no reaction from the fob or when I turn the key..

Further, as I checked the car earlier on, there was a fault code related to the security ECU. I found it in the bood, in accordance with your instructions. Do you think I should try and replace it with a used one, and in that case, do you know if they are interchangeable, or do they need to be worked on before the car can accept them?

Kind regards

Ivar Langseth

 

By the starter relay not clicking splits the starter not turning over in half . No need to remove the starter .

Starter solenoid fuse ?

Best ro charge the battery to 12.77 volts because as the voltage sags below 11.4 the ECU fails to give ignition




you can swap the starter relay with one not used like the heater water pump or one with markings of the same part number




To get the engine running as a trick you can completely bypass that circuit by removing the connector just behind the valve cover that is mounted along with the 2 , 4 wire O2 sensors . As you remove the connector you will see a single pin in the down direction toward the starter below . If you put 12 volts on this pin you control the starter and it's bringing in the heavy gauge battery source power , no need for a heavy jumper wire and you can source the 12 volts from the post on the firewall . You will need to have the key in the run / on position .

We can look at the ignition switch and if the pin 1 is closing , easy to get to .




And we can do a " Hard Reset " on the battery cable since the SLCU is hot at all times if the SLCU is out of sequence hence the FOB also faulting .

Keep asking questions .

Editing

 

In markets outside the USA the security module is matched to the transponder chip in the ignition key.
If the module is changed it must be configured to the key using dealer level diagnostics.
The security module does not simply inhibit the ECU using a single connection and cannot be easily disabled.
What was the fault code? Fault code P1621 can be listed for reasons that have nothing to do with the security module, for example random misfires.

On turning on the ignition all of the warning lights on the dashboard should come on and then go out except for the Check Engine Light.
If this light does not remain on at the end of the ignition on sequence then cranking is not possible.
Cranking is also inhibited when the transmission selector is not in the Park "P" position.

 

The remote (fob) operation is probably a separate issue from starting. Did you put in two CR2016 batteries? If it has lost its association with the car there is a link in the HOW TO sticky about reprogramming it to the car.

A couple of months ago I went swimming with my car keys in my swimsuit pocket. Realized this about ten minutes in. Took apart the fob, let it dry out along with the batteries, put it all back together. I wasn't too optimistic about it surviving, but it did! Even using the same batteries. Didn't even lose its programming. I was impressed. And lucky too.

 

Thank you again, Lady Penelope

I have gone through the car step by step. The remaining things to check out are the pin connector in the ignition lock, and the bypass operation. I will try it, but as it is a German version it is equiped with the anti theft system, it might need more persuation to let go of its hold on the immobilizer. You pictures are really helpful and I start to fully comprehend the system that has to be defeated here. I am currently on autumn break in Spain, and will get into the car as soon as i return to Norway.

All the best

Ivar Langseth

 

I typed out a long reply but lost it when Windows 10 went wacko .

Make America Great again / Fix Windows 10 ...............You want him in your country so you don't have to laugh at his stupidity from afar ?

The real secret to a genius is they will never tell you , I'm just saying .

 

Thank you for writing me a long answer. I am also familiar with the Windows 10 bug. Horroble thing.I to tried to post an answer, but it got lost and I am trying again.

Since our last conversation, I have been on a journey abroad, but got right to the car on my return last Sunday. That day I tried out your tips. The result was not start again, thought the engine turned when I put 12 volts on the contact you showed me. This might have something to to with the orange "Check Engine light" not being illuminatde when the key is in position 2.

. I have also acquired a complete set of ECU, Body Security Module, ignition lock with key and transponder ring. I used the best part of the Sunday on installing these donor parts. They came from a car that ran when being dismantled. The only thing that changed was that the knob in the dash with a picture of a key and a door stopped being illuminated all the time, and the right hand headlight constantly illuminated.

. The display for the climate controll started giving five beeps and the letters "Er" when i tried starting the car.

So, if you have any other traces to follow, please let me know :-)

All the best

Ivar Langseth

 

Hello and thank you for your reply
I have dissected the fob. I contains only one battery...

 

Hi Ivar
Did you ever solve the problems on your Jag?
I have a danish X300 1997 which suffers from the exact same symptoms as you describe:
- no engine crank, central- and remote locking not working and the dashboard Check Engine Light goes out after the ignition sequence.
...and like you I have a new battery, fuses OK and Body Processor Unit replaced with a used but working one.

Does anybody know the probable cause why the 'Check Engine Light' go out after the ignition sequence, when it apparently should stay on?

Best regards
Jesper
Denmark