OK, I know this is similar but I can't find quite the same instance as mine. Bought a used car in the Spring. Only issues seemed to be possible alignment, blown speakers and a trunk that opened too easily.

Replaced the shot speakers and was happily motoring but didn't drive regularly (Only live a mile or so from work & only used on inclement days). One day went to start and key fob wouldn't respond. Assumed it was the battery and borrowed charger but discovered battery had full charge.

Power locks & alarm don't respond. Googled and found inertia switch (Someone had hit my car without my noticing exactly when) but felt no response from button so assumed fine. Then I remembered had a faulty J gate sensor in previously owned XJ (Where a shift wiggle was required once) and tried actually taking apart & putting in neutral . Alas, no difference. The same results. Have to unlock manually, go to start, power shows, dash lights come on & off as typical except check engine (which stays on until started, correct?); I hear a click coming from passenger side (I think) and 10 beeps but nothing else. Radio works, headlights switch on. Power seats & windows do their stuff. Only other thing is shift is locked too.

I'm at a loss! After googling thought it would be the BPM (ECU the same thing?) bought bought a CarMD code reader; thinking it's going to tell me what's wrong since there are soooo many electronic systems in Jags. ...Maybe not; it's reading a likely ignition plug/coil scenario because of the check engine light (Code P0300) . But not sure if I trust it because don't all cars show that until they start to run?!?

Maybe I should've shopped for a better code reader; I saw a web page once of vast codes & meanings for Jags.

Anyone have any ideas? Most local mechanics who'll come to me don't seem to want to try & tackle this!

 

When you say that the "Shift is locked" I'm assuming you mean that it wont come out of Park? If so, this is the "shift lock solenoid" which you should hear operating when you press the brake pedal, allowing the shifter to be moved and also to avoid starting the car in drive/ reverse. The shift lock can be operated manually by unscrewing the plastic torx head screw on top of the centre console/J gate assembly and just insert your key/biro/ similar down into the hole to depress the lock tab, thus releasing the shifter.

Even though your shifter seems to be in Park, it may not be clearly so, if the "Not in Park" switch under the ski slope is misaligned. (3.2 litre models only. 4.0l is operated by a rotary switch thingy on the gearbox, apparently!)

Place the car in neutral and then try. Failing that, the power supply to the solenoid in question is fed via a switch on the brake pedal itself. These can apparently fail. Others will have experience and info on this.

Keep us posted and good luck.

 

Took ski slope apart (didn't get how release worked at first) and manually released & put in neutral; no difference.

 

Do you hear or see the solenoid operating when you press the brake pedal? Are you getting power to the solenoid when you press the pedal? Is there power getting through the switch on the brake pedal. Remember, there should be two switches, one for brake lights and the other for solenoid. Is your car a 3.2 or 4.0l? The inhibit switch under the ski slope can go out of sync, but has some adjustment. And remember, when you select "D" it should glow red, otherwise it's not working right. Aside from that, is your starter motor and starter solenoid working ok? Are they getting power? There is an ignition relay up front, behind the headlamp cluster (Drivers' side, I think on RHD cars) Worth looking into?

 

Well I do appreciate your input but I'm afraid you were totally off!

In this forum others hinted at similar symptoms suggesting the BPM (Body Processor Module). My 1st instinct was that but a professional mechanic said I shouldn't throw parts at it! He was wrong!!! After I replaced the BPM, it started right up!

What I want to pass on is the parts seller (who stated he had much experience in such matter) listed these major symptoms indicating the BPM being faulty;
1. No power locks
2. No headlights
3. No wipers
Those were consistent and the car started right up after BPM replacement!

Of course now I've discovered another separate issue; still love my Jag! Third one I've owned!

 

Good stuff and glad you got it sorted! Thanks for the tip and that's a problem with these cars. Quite often any given issue can have numerous possible causes. Happy motoring!

 

Well, Before I could attend to the possible alternator/charging issue. After recharging the battery & considering driving by a shop recommended to me (Alternators, Belts & Electrical work aren't fun!) I'm running into the same issue.

So NOW I have to decipher WHAT can MAKE a BODY PROCESSOR MODULE be 'killed' as the car is exhibiting the EXACT SAME symptoms as before I replaced the BPM. Otherwise, I might be at this forever.

All I know is; after replacing the BPM; the car started right up with a recharged battery (It'd been sitting for many, many months!) but a belt was squealing terribly and I could smell burn't rubber–So I was hoping maybe just the alternator wasn't working at it's best & might not have to be replaced.

I also know that even though the car started up & drove the locks still were out but I believe that could be a reset issue as it was without power for some time.

Any body with any other ideas they can think of, please chime in! I'm not against paying a shop to fix it but I don't want to pay for someone to educate themselves on the intricacies of a Jaguar!

 

Have you downloaded the electrical guide from the 'How to' sticky? With that and a multi-meter, it's a pretty simple circuit to troubleshoot.

Essentially the ignition switch feeds a start signal to the BPM. The BPM sends a start signal to the starter relay, provided the transmission is in park or neutral and the check engine light signal is present. The relay then allows the starter motor to spin.

My guess is that you have a flaky Park/neutral switch or ignition switch but that is just a guess. Tracing the circuit will give you a definitive answer as to the problem.

 

Or like me you might just need to clean up the ground strap running from the drivers side fender to the engine block?

Got my car running lickity split

 

I am going to GUESS that maybe the original BPM was NOT The fault and the replacement process did something to reset or reconnect some dodgy electrical connector. That analysis is based solely on the lack of other reports of failed BPM, so it is only my guess.

I agree that the correct way to resolve this is by tracing the electrical circuit using the schematic and a multimeter. I would certainly try a "hard boot" and try again.

That said, your symptoms could very well indicate a BPM failure. If it is another failed BPM, then your report of burning rubber smell could indicate a bad voltage regulator and excessive charging voltage from the battery. If you are pretty sure your original problem was solved by a BPM, install another one, then carefully monitor the battery voltage to make sure it does not go above 14.8 volts or so. Another possibility is that the leads got crossed during the jump off.

BTW, if you believe in the metaphysical, then your second failure resulted from you telling a poster "I'm afraid you were totally off". Even if his suggestion did not fix your car, it was not "totally off" if it was a valid suggestion that matched the symptoms. And it was.

 

Like I said, diagnosing issues, especially non start or electrical gremlins, can be like starting a family tree. I don't think the OP meant anything negative by his "way off" remark. As you implied, my suggestion was only one of countless possibilities. The important thing is that we pool and share our knowledge, however limited or "way off", which is after all, the main purpose of this forum. And I hope the OP keeps us posted and adds to that pool of knowledge.

 

Well, Sogood, that's an honorable outlook. My point was not to chastise as much as to remind the poster that suggestions can be valid although not ultimately sucessful. Anyway, it does sound like he has a little mystery going and I, too, hope he keeps us posted. I supect a SCLM problem might be involved, but there is at least some inconsistency in the symptom description. In the original post, the headlights switch on, then they don't in the follow up...

 

True. Some posters tend to forget that the original fault description can be just as much "way off" as the diagnosis. It's very important to give as much clear detail of the problem as is possible. Doctors rely on such information from their patients for the same reason. I have actually seen posts on other forums, covering all types of cars, which might simply say "My car won't start. What's wrong".

Anyway, the joys of motoring! And thanks for your input.

 

Yep, in medicine and cars, the "differential diagnosis" can be key.

 

Gremlins....that's it! Must've left food in the car after midnight. I have to admit! I've only been able to tinker on weekends on sometimes work them so this began months ago and I can't totally remember if the headlights worked before.

Please don't anyone assume I mean anything disparaging towards them.

This is my 3rd Jag & the only one that's giving me a challenge. I remember turning on my lights but maybe that was before the trouble. My voltage never got above 12 (After replacing BPM) which is why I kept having to remove & slow charge my batt. Does anyone think that could've affected it? The parts dealer thinks a short but reading schematics isn't for me.

I assumed a belt wasn't functioning properly as it was immediately after 1st start post BPM replacement and the belt(s) {unknown which} squealed for several minutes and then I noticed a burnt rubber smell. I wondered if the Alternator was sluggish. My accelerator a t 1st wouldn't even react o pedal movement. I idled around my parking lot until the car warmed up. Then I turned on lights & blinkers (Car had sat months) & it died. Next day after charge started right up again. Drove a few miles & noticed voltage kept dropping.

Only Time to work on is weekends & last weekend realized car back to orig state. Did notice relay missing by block in trunk but if correct it's only thetrunk release one. Is there some secret English handshake I missed reinstalling battery? Have to remove as no way to safely charge in-car.

Hope the Holidays are good for everyone. Thanks to all for your input. Miss being in a big city with many Jag repair options to choose from. Two professional mechanics shunned even trying so wary of even recommended shops (until from a fellow owner).

It's funny; I owned my 95 in 98 & it was so trouble free I had minor stuff done by Pep Boys! I guess an extra ten years makes a difference.

 

Almost forgot, maybe a short makes sense. I first charged battery a month ago before replacing BPM & battery was well drained after slow charging for days (When left connected). But then again, maybe accidentally left a light on as noticed dome on after had repaired, installed batt & started. Can't say for sure.

 

OK, lets go after this a piece at a time. The burnt rubber smell is either the alternator belt, the crank damper dissambling itself, or an electical short. I think it would be a good idea to figure out which. If it is a short, which seems far fetched- a fuse should blow. I assume your have an alternator belt problem, or a battery discharge issue. Use an ammeter connected in series with the battery to detect a parasitic discharge after the car has been off for about 15 minutes. See the recent post about the car thinking the key was still inserted.

So, with the battery connected to another car with jumper cables, exactly which functions do not work? Please be specific.

 

I had similar mysterious problems with my 1996 XJ6 for years. Replaced battery (more than once), cleaned starter, cleaned rotary switch, checked starter solenoid relay, replaced BPM. After replacing the BPM things were OK for a while, but then the problems returned. Finally discovered that the big positive cable from the battery to the starter is not a continuous piece of wire; there's a connection where it passes through the firewall. This is beneath the carpet on the passenger side of the car (here in the U.S.), near the center transmission hump. On my car, this connection was loose, causing various electrical gremlins, including non-starting, occasional stalling and low voltage readings on the instruments when running. Also, judging from the charred, melted nylon which served as the insulator where the cable passes through the firewall, it might easily have set the whole car afire. Once I found and fixed this, life got a lot better. As far as replacing the BPM goes, I realize now that, as the BPM is behind the glovebox, I probably jostled this cable connection while replacing the BPM, as I was squirming around on the carpet in that area while doing the replacement. That's why I initially thought the BPM replacement had solved the problem when, in fact, it had not. Just something else for you to check. Good luck.

 

I agree with tsfo2. I recently fixed my Jag XJ6 Sovereign 1997 no starts and having to carry a remote battery to be able to start my car because the battery would not start and the alternator would not recharge the battery. It was a melted connection on the right firewall of the positive cable as it goes to the starter with an approach just behind to glove compartment, and in the front covered by a black hood. Then after that repair, it was a poor connection because I only put one of the M8 1.25 nuts back and it needs both to sandwich the connector going to the solenoid for a good tight connection. I also got a $6.50 cigarette lighter voltmeter with led lights that shows you battery and alternator voyage that has been helpful when the car voltmeter had its swings.

 

I agree with tsfo2. I recently fixed my Jag XJ6 Sovereign 1997 not starts and having to carry a remote battery to be able to start my car because the battery would not start and the alternator would not recharge the battery. It was a melted connection on the right firewall of the positive cable as it goes to the starter with an approach just behind to glove compartment, and in the front covered by a black hood. Then after that repair, it was a poor connection because I only put one of the M8 1.25 nuts back and it needs both to sandwich the connector going to the solenoid for a good tight connection. I also got a $6.50 cigarette lighter voltmeter with led lights that shows you battery and alternator voyage that has been helpful when the car voltmeter had its swings.