I am deep into a full restoration and the ignition system is blocked out by the security/radio/anti theft system. I have a brand new starter, starter relay and battery. The radio says CODE. From reading what other members say, I can get the code from the dealer. Since I plan on driving this car often. I would like to replace the original cassette deck/radio with a new 2018 jaguar model. Does anyone know If the ignition security system can be bypassed. This block will not allow the engine to even turn over. It sucks. Please help!!
Welcome Steve,
For all I know, the radio and the ignition have nothing to do with each other.
Further, the XJ6 Series I thru III did not have any ignition system security, especially from the factory.
Check if you don’t have an XJ40 (which might have anti-start protection) and check the usual issues, that is if your fuel pump runs when you turn the key, what the ignition/starter relay does, where you have power.
Later on, you should be able to replace the radio with any DIN (standard size) radio as far as my knowledge goes. I have a BMW unit in mine and it was very doable. Every time the battery is disconnected it will, of course, show CODE.
Think about it the other way: if your radio would communicate with anything engine related then it would not be swappable. If it’s ye olde XJ Series model and not the „40“, look for standard no crank - issues.
David
Steve,
Your 1986 XJ6 did not come from the factory with any ignition system anti-theft system devices. If your car has such a system then it was an aftermarket system installed by the dealership or someone else.
Your car did come equipped with a Security Radio that requires the proper code to be input after power has been removed from the radio. The Security Radio has not function that disables the ignition system. If the Security Radio loses power it can not be used again unless the proper code is input. That is the only “security” feature to it. I removed the Security Radio from my former 1987 XJ6 Vanden Plas when it stopped working and replaced it with an aftermarket one from one of my parts cars without any problems, except for all the soldering required to accommodate the more modern radio connectors.
Paul
Thanks david, I do have an 86 XJ6. It does have a Jaguar brand radio/security unit. If you do not input the proper code it will not allow the start/ignition system to activate. Other members have also had start issues with this Jaguar/aftermarket security system. I know it is not factory, but many XJ6`s have had them installed directly after the factory release. If you don’t have the correct code, what switch/relay is not activated to allow car to start? Thanks
Thank you Paul, I just checked and the thick brown wire going to the starter relay (on fire wall near engine) has no power. I found no power at all to any of those wires on the relay. The brown wire which has a fuse turns into brown/purple and goes somewhere in the right front engine compartment. Where would you look if you had no power to the starter relay?
Steve,
Please post a picture of the radio that you have in your car. From your posts it sounds like some installed a radio tgat was not correct for your car and as a result it will be impossible for us to guess what modifications they might have made to your factory wiring. Perhaps if you posted a picture of your radio someone might recognize was model it originally came in and that might lead you to clues of how it is wired in your car. Otherwise we will all be shooting in the dark.
Paul
Steve,
Do you have a copy of the Series III Service Manual or the XJ6 S57 Electrical Guide? They are both very important documents to own if you are working on this car andbthey both show the answer to your question in their wiring diagrams.
The Brown wire going to terminal C2 on the starter relay gets it’s power from the Right Terminal Post on the firewall inboard of the battery. If you are working in this area please disconnect the cable from the negative battery terminal. There have been more than a few posts over the past 18 years that I have been a Jag-Lovers member where someone was surprised, to say the least, by what can happen if you leave the battery connected.
Paul
Paul, I just jumped the starter relay power terminal to the positive battery terminal and presto, I turned the key and my beautiful Jag started to purr for a second. I just completely rebuilt the fuel system. New injectors, fuel lines, fuel pump and every other part needed. Do you know of a way to prime the system or do I just hold the key for awhile. Getting back to my original problem, the brown power wire going to the starter relay has no power. I traced it to the front right corner of the engine compartment. It looks like it could be going into a connector to a little aluminum box. probably 2 inches by 3 inches. Where does the thicker brown/purple wire go to to get its power? Thanks
Wait a minute. All solid brown wires have constant battery power. To prime the fuel system either put it in gear and turn the key to start (it won’t turn the engine) or remove the air filter and push open the flap of the air flow meter.
For the wire, check the wiring schematics Paul mentioned. But all solid brown should go to or come from the two posts at the bulkhead (firewall) or the battery.
If it only runs in “start” then your ignition switch might be faulty? Or it might get no fuel when running. Look at the wiring guide and check all relevant connectios, you’ll figure it out.
Steve,
One way to prime the fuel system in a properly configured and running Series III XJ6, put the automatic transmission shifter into Reverse or Drive and turn the ignition key to the start position. This should not start the car if the Inhibit Switch is working properly but you should hear the fuel pump running as long as the key is in the Start position.
Please post a picture of that little aluminum box. It doesn’t sound like any OEM part that I am familiar with but of course one picture is worth a thousand words. If I saw a picture of what you were asking about I am sure that I would be able to tell you if it was OEM or aftermarket.
BTW, speaking of pictures I would sure like to see a picture of the Jaguar Security radio that you believe has disabled your ignition system. That is a new one to me and I have owned and worked on several Series III XJ6s and one XJ12 over the past 18 years.
Paul
If the aluminum box really makes and breaks the brown wire / power to the starter relay it would make sense to bypass the box for a start. But I have a feeling that if this is really the case the box would also break power to other parts of the ignition so if would be worth sending us a picture. And going over the connections. I know of two aluminum boxes in the front of the engine bay, being the ignition amplifier which is a square bolted to the intake plenum, and one being the power resistor for the injectors, see Lucas 2PR for a picture. Anything else would be aftermarket.
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That ‘box’ is likely the control unit of the aftermarket security system, Steve - but it should then have more than two wires. And can those wires be easily disconnected…?
Unless you have the manual for that security system and intend to use it - it should be removed, or bypassed. Bypassing an alarm system without knowing what it actually does, is somewhat intricate. That the radio code is used to turn off the security is somewhat unusual - and getting the code from a dealer should rightly involve even serious bureaucracy than for the radio alone. The more usual security trigger is a wireless remote - using the radio as trigger seems cumbersome…
Changing the radio will not automatically solve the problem - only the proper code for the proper radio, that triggers the control unit will do that. However, it may be possible to trick the control unit into believing that the correct code has been entered - though this may not start the radio. A check of the wires at the rear of the radio may clarify how the radio is connected to the security control unit - by wire colours…
Specific question; does the electric antenna operate? If not; the ‘ant out’ connection may be used to trigger the control unit - and bypassing the code is then simple, unless the radio sends a coded message to the control unit rather than plain power…
You mentioned that jumping battery power to the starter relay cranked and started the engine, ‘purr for a second’ - then quit…? In which case; the control unit also cuts ignition power. In which case; jumping the battery to coil pos as well as to the starter relay may keep the engine running. But the security system may be more sophisticated than that…
As an aside; as David says, all brown wires has permanent power. And there were no fuses originally involved in engine management systems, blown fuses would not affect engine running. So the fuse is associated with the security system…
As a second aside; priming the fuel system is rather pointless. The pump will pressurize the fuel rail within a couple of seconds, and pressure will be retained in the rail for ‘some’ time courtesy of the non -return valve. If that valve is defective; the rail is instantly depressurized whenever the pump is stopped - nullifying priming…
Frank
xj6 85 Sov Europe (UK/NZ)
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Frank, I agree with all you said but would like to add that jumping the ignition might not do it: It might cut power to the coil, but it might just as well cut the fuel pump (if it runs for a few seconds-) or the ECU (most easily accessibly: the trigger wire coming from the coil and entering the injector loom) or it is a simple case of opening the AFM and checking the safety switch that activates the fuel pump only when the engine is sucking air. That, or the ignition switch.
In what state was the car when you got it? Did it run, etc.?
I’m with Paul. A bare minimum in resolving the question is the S57 schematic. At least one could see the color on the wire and refer to the schematic to identify it.
BIG clue!!! Brown means always “hot”. No volts here is a sure clue that a connection is bad, the wire is busted, or a Security device has created an “open”.
WAG. Sans picture the ID of the alloy box is just that. Could it also be a "tin’ silver box ? The original Jaguar start relay meets that definition.
Yeah, way back I learned of radio codes!!! but, the one that taught me was just dark, no matter what. I tossed it in a hissy ft… The ide was to deter thieves from stealing "stereo systems from “late model” cars. Once quite popular…
A product of “Mid n 9ght Auto Supply” !
Carl
Hi Paul, I believe that I made a mistake about the aftermarket security/radio disabling the ignition system. I have since found the brown wire disconnected from power, I fixed that problem and now the engine cranks but does not get fuel. I did not hear any noise at the fuel pump and the fuel gauge does not move when the key is in the on position. The aluminum box I mentioned turns out to be the power resistors. Thanks Paul
Steve,
Thank you for solving that mystery, which in this case was no mystery at all. Very little of what is discussed on the XJ list is new. I was hoping that you really did have something new and different in your car that hadn’t been discussed before. Oh well, 
Please take advantage of the extensive FAQ section on the old Jag-Lovers.org website, I think that it covers everything you mentioned as current issues with your car, and muchuchore
Here is the link: www.jag-lovers.org/xjlovers/faqsandinfo.html
In addition, the Series III Service Manual, the Series III Owners Handbooks, Parts Cataloge and S57 Electrical Guide are all very helpful documents to help you sort out what parts are in your car (or not), how they work, and how to repair them. Jag-Lovers is very helpful to fill in the gaps and provide lessons learned.
Paul
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By design the pump is not active in ign ‘on’, Steve - the fuel relay is activated by the key to ‘crank’.
When the engine is running; the fuel relay is activated by a reed switch in the AFM. The best way forward is to jump the fuel relay - easiest by disconnecting relay and short the white to white/green on the base. The pump should now run with ign ‘on’ - and any problem can be addressed at leisure…
Like Paul; I hoped we had a juicy problem on our hands - not a run of the mill one…
Frank
xj6 85 Sov Europe (UK/NZ)
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Since there seems to be no security involved in Steve’s case - it is rather academic, David…
But indeed; any security system worthy of its salts should not be that simple to override/bypass. The former cases where aftermarket security/alarm systems posed problems - it was not a walk in the park…
Frank
xj6 85 Sov Europe (UK/NZ)
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Frank,
I jumped the fuel relay as you suggested and the pump still will not activate. In your diagnosis, keep in mind that I am doing a full restoration and all lights, antenna, side mirrors, door lights, horns have all been removed.
I do not know If having something disconnected could cause no power to the fuel pump. I still have the word CODE displayed on the radio. I have the dash apart to remove the radio, but I am not ready to do that until I get the engine running again. Frank, If you have any ideas let me know. Steve
There’s a safety switch on the passenger side where the A post goes vertical. Check that, and do you have no power or can the pump be dead?