S type 4.0 won’t turn over

Hello guys… I’m new here and having trouble
With my 2001 s type v8… whenever i turn the key to start position the lights on the dash goes out… looks like there’s no power… battery is new … any help please

Hello Jed - welcome - don’t forget to go to your profile section to list your country, since this is a global site, so others close to your location may be of help to you - as a SAFETY note, do not attempt anymore starts yet - the loss of all electric, when the ignition key is in the start position, usually is a sign of the starter circuit battery positive path (also called the “hot”) having a direct short path to a battery negative path (also called the “ground”) when the ignition key is in the start position - due to this short path, the starter circuit wiring can become very hot, to the point of melting insulation on the wiring, and may start an electrical fire - you first need to disconnect the negative battery cable, at the battery - you then need to check the positive side of the starter circuit wiring, visually, and also with an ohm meter, to find where the circuit is shorted to ground - once found, and repaired, you should be able to reconnect the negative battery cable, at the battery, and then using the ignition key, start the car in a normal method - Tex Terry II - 1991 XJS Classic Coupe, 1986 XJS Coupe - 4/7/2020 0223hrs. EST USA.

Thank you for your input texterry… i will check the wires tomorrow… i will keep you posted. Does it have something to do with the ignition switch? I was planning to remove it…

Not much to go on here. Have you scanned for codes? What happens to the security LED when you put the key in the ignition barrel? It should come on for two seconds then go out and stay out. If it flashes, this can indicate an immobilser problem which is preventing the engine from cranking. In this case, you may well find you have a P1260 fault code.

Hello Jed - what I wrote will apply to almost every vehicle - without the electrical wiring schematic for your vehicle, I would not be able to tell you the positon that your ignition switch is located in the circuit - generally the ignition switch provides a path for the “hot” path to activate the starter solenoid, which in turn activates the starter motor - when the starter motor circuit is activated, a large amount of amperage (electrical power) is used to operate the starter motor - a “short” path in this circuit will use a very large (usually all) amount of amperage which then is indicated by nothing being available to operate anything else, hence the loss of your lights - usually there will be a large size wire connected at the starter motor that contains the path for the positive “hot” battery power - the starter case, being bolted to the engine block, provides the negative “ground” path - when the starter solenoid is activated then a connection is made, within the starter, between the “hot” and “ground” paths, to make the starter motor operate - if the starter motor is faulty internally, there may be the short that is increasing the amperage usage - you can visually check for poor wire insulation, on the positive “hot” wire, or use an ohm meter to check for a “short to ground” on the positive “hot” starter wire - remember to first disconnect the negative “ground” cable at the battery prior to testing - If no one chimes in, with knowledge of your vehicle circuit, I should be able to still help you troubleshoot your problem - Tex Terry II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - 4/7/2020 0343hrs. EST USA.

S Type 2001 Electrical Guide see Fig 02.1:


Hello Neil - that is very kind of you to post a link for the electrical schematic for Jed’s 2001 S-Type vehicle - once he looks at this he should be able to find the problem - I will be able to use this also to assist him through his testing - Tex Terry II - 1991 XJS V12 Classic Coupe, 1986 XSJ V12 Coupe - 4/7/2020 0405hrs. EST USA.

Hello Eric - since Jed mentioned that the dash lights went out, when he turned the ignition switch to the start position, I did not think the immobilizer circuit was involved, but with your being familiar (more than I) with this vehicle, maybe he will notice your message and check what you stated - Tex Terry II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - 4/7/2020 0414hrs. EST USA.

It’s confusing unless you know the car. All of the lights except the SRS light go out when you turn the ignition to position III (cranking). I was just suggesting a quick check that you can do from the driver’s seat.
The starter won’t turn unless the starter relay closes. Power to the starter relay is provided from fuse #1 in the primary junction box but it has to go via either the park or neutral switch, one of which has to be closed for power to reach the starter relay. (Jiggling the Randle Handle can sometime reveal a dodgy switch).

Even if the starter relay has power it won’t close unless it gets a ground from the Instrument Pack. The IP receives signals via the SCP bus from General Electronic Control Module and from whatever anti theft system is installed. This is different for different markets. I think everyone gets the PATS but not everyone gets the key controlled immobiliser.

If all seems well from the driver’s seat, then the first check is to see if the starter relay has power when the ignition is in position III. (Tag 86) If it does, and it’s not closing, dab a ground on Tag 85 and see if it closes and the starter cranks the engine. The engine may not run for other reasons but at least you are in the ballpark. If this is what you find then you have to investigate why the IP is not sending a ground when it should.

Hope that helps.

Thank you very much everyone for the inputs.,., i was able to start it last night…
i will go ahead and check the wiring right now
I just woke up from figuring stuff out last night
Again thank you very much again everyone.
I will keep you guys posted…

No codes at all… the red light turns on for a bit then goes out… I’m waiting for the rain to stop then I’ll check the wiring as texterry suggests.
Thank you-

Thank you mr. Neil for the link… definitely helpful.

Hello Jed - glad you are making headway - will look forward to reading your upcoming post(s) concerning your findings - Tex Terry, II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - 4/7/2020 2227hrs. EST USA.

The other useful resource is J-L member Gus’s website:
Which covers many of jag models.

Finally found the culprit… It ended up being the key… i was able to take out the ignition switch and cleaned it… at first i was frustrated because it did not work… still no power on the start position… then while cleaning the tumbler, i noticed that the notches to the key fob are gone… i asked the wife for the spare key and boom works perfect…, Thank you very much everyone for the help… glad to know that there’s a site like this one…, definitely helpful… hopefully we can get together some sort of a jag nite.,:stuck_out_tongue_winking_eye:

Hello Jed - new learning for me concerning the key discrepancy - wonder what affected the key - glad you are back up and running - Tex Terry, II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - 4/11/2020 1940hrs. EDT USA

I take it back textterry😔 tried starting it again right now and the same… i jumped the starter relay so that eliminates the starter right… don’t know which route to go now…,

Hello Jed - as Eric mentioned, in an earlier post, try slightly moving the shifter handle (while you have the ignition key in the start position, and the shifter handle in the “Park” position) to check for a possible bad connection of the safety neutral switch - you can also perform this same test with the shifter handle in the “Neutral” position - Tex Terry, II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - 4/11/2020 2243hrs. EDT USA

image Hello textterry … see attached pic

The groove is gone on the other key…