I have a 2004 Jaguar S Type V6. The check engine light was flashing. I changed all the spark plugs, ignition coils, gas filter, air filter and the upper manifold gaskets. However, the check engine light was still flashing. I took it to the mechanic. He diagnosed a defective ignition coil (even though I replace all of them w/new ones). I decided to change it myself. I went to the store and swapped it for another one. He said that if I did not have a OBD to reset the check engine light after replacing the ignition coil that I could disconnect the battery and join the positive with the negative for a couple of minutes to reset the computer. After I installed the new ignition coil, I went ahead and disconnected the battery and joined both terminals for a couple of minutes. Then, I connected the battery and now the car is displaying the following messages: Gearbox fault, Parkbreak fault, Abs fault, Dsc not available. Now, the car does not start at all!!! When I connect the battery, it beeps rapidly many times for about 15 seconds and then it stops. Any help is really appreciated!!!

 

Sounds like you've got two problems going on at once.

In the immortal words of Douglass Adams - Don't panic!

For the no-start condition and all the new warning messages (everything but the flashing check engine light), that's likely caused by low battery voltage. These cars are VERY sensitive to low prestart voltage. So please beg, borrow, or steal an automatic charger with at least ten amp output. No trickle charger, won't cut it. Make sure your battery is fully charged before doing anything else. This is very important. Don't skip this step.

Remove the short negative battery cable where it bolts to the body. Clean both surfaces to bare metal. Apply a thin coat of dielectric grease (the stuff used on spark plug boots) to both surfaces and reassemble. This is a known problem area for corrosion. When you previously moved the battery cables, a marginal connection here may have been disturbed and caused all the new faults you suddenly got.

Between cleaning this connection and charging the battery, that should hopefully clean up a lot of this mess, leaving just the misfire/flashing light problem. If those other faults are still present, let us know and we can walk you through some more steps.

If you are now able to start the car, it is VERY important to NOT drive with the check engine light flashing. When the light flashes, that is meant to grab your attention that you've got a problem bad enough to melt a catalytic converter, a very expensive proposition. A typical misfire can be a medium level kind of problem, where the computer brings it to your attention by turning the light on steady so you can get it checked out reasonably soon. But when the light flashes, the problem sensed is bad enough that you should pull over as soon as safely possible. Please don't toast a cat by driving any more.

For troubleshooting a misfire, you will need a scanner (preferred) or a simple code reader. You can get a basic code reader for around $20. You'd be working blind without one. The beauty of reading the codes is you can quickly determine which cylinder(s) is at fault, no guesswork involved. So if you can please report back with the exact codes, we can walk you through the next steps. You should have some 5-character codes like P0301, P0302, etc.

if you don't have the ability to retrieve the codes, most auto parts stores will do it for free. The only catch is you shouldn't drive the car with the light flashing. You would be okay to go a short distance at low speed as long as the light doesn't flash. But if not possible, you'll have to bring a scanner or code reader to the car. Remember, get the 5-character codes, not just what the machine calls them.

Lots to digest for you so far, and lots more to throw your way, too. But for now, please take these these three preliminary steps (charge battery, clean ground connection, read codes) and report back. Deep breath, the car will live...

 

Thank you so much for helping kr98664! I will take the battery to a car auto parts tomorrow. I believe they can charge the battery for free. I will clean the connections and apply the dielectric grease. Do you know what is the battery's minimum required voltage/amperage for the car to start? When I disconnected the battery it reads 12.07 volts and when I connect it reads 11.82 volts.

 

Those voltage readings indicate an essentially dead battery. You need at least 12.6v prestart. That fraction of a volt may not seem like much, but it’s the difference between dead and fully charged. Even if the battery had enough charge to properly power the starter, guessing around 12.3v, you still need it fully charged at a minimum of 12.6v so all the various modules power up correctly. This isn’t like cars of old, where if the battery had enough oomph to spin the starter, all was good.

Most parts stores can charge a battery, but you’ll have to leave it for at least a few hours, preferably overnight. Have the battery tested for overall health and state of charge, too. These are separate values, usually stated as a percentage. Don’t be surprised if your battery fails. Remember, these cars are very persnickety about the battery, so don’t try to make do with a marginal one.

Edit: if you have to replace the battery, ask to have the new one fully charged. Most new batteries don’t have a full charge at the time of sale. Might be adequate for most cars, but not a power-hungry Jaguar.

 

Thanks! I will keep you posted tomorrow.

 

The parts store charged my battery. I connect it to the car but it did not start. I checked the voltage reading and it came back with 12.4V. I guess I have a bad battery. I will be going back to the parts store and buy a new battery. I will let you know once I try it out. Thank you!

 

Some quick comments

1) Please clarify exactly what happened when the engine "did not start". Did the starter engage and spin the engine at a normal cranking speed, but the engine would not run on its own after the key was released? Or did nothing happen when you turned the key to start, or maybe just a click or hum, but no movement at the engine? Huge difference here in how to proceed, so more detail is needed.

2) Was the 12.4v taken after a failed start attempt or two? If the starter had actually engaged, 12.4v might be normal.

3) Did the shop ever test your battery, or just charge it?I

Don't mean to overwhelm you with questions, but want to make sure I don't send you down the wrong path.

 

Thanks for asking!

Here are my answers:

1) The car did nothing. The starter did not engage. There was not a click or hum. No movement at the engine at all. It behaved just as before the battery was charged. The car is displaying the following messages: Gearbox fault, Parkbreak fault, Abs fault, and DSC not available. When I connect the battery, it beeps rapidly many times for about 15 seconds and then it stops. All the lights in the cluster are on.

2) The 12.4v were taken before and after trying to start the car with the battery disconnected. When I connected the battery the voltage dropped to about 12.27v.

3) The shop tested it too. They tested it to make sure it was a good battery before charging it. The test came up ok.

 

I'm not sure what's going on with the battery voltage. That's too low for a good clean start that will let various electronic modules power up properly and extinguish most of those fault messages. However, it should be adequate for what I'll call a messy start, where the engines fires up even if other stuff still misbehaves.

In light of that, let's concentrate on the most glaring fault, the no-crank situation:


Look at the indicator lights at the base of.the shift lever. P or N must be illuminated or the starter will be inhibited. If anything else is on, wiggle the shift lever and see if that helps.

Next, observe the PATS (Passive Anti Theft System) indicator light on the dash, at the base of the windshield. This is for the security system, which may have inhibited starter operation as a precaution. Here is how it's supposed to behave if all is good:

Lock the car with your fob. Click the lock button a second time to arm the security system. The horn should chirp once. Watch the little red light. It should flash once every 3 seconds or so (not sure of the exact time) to show the system is armed. Now unlock the door. The red light should go out. Now hop in the driver's seat and turn the key to RUN (Not start yet). The red light should come on solid ONCE for about 3 seconds and then go out. If it flashes anything after that, you've got a stored fault.

Please check those two things and let us know. I hope you're not getting discouraged. None of this stuff is a show-stopper. We've just got to methodically work through some basic stuff.

Anybody else have any ideas? Perhaps I'm overlooking something obvious.

 

Two more ideas for the no-crank condition:

1) Did you clean the ground cable connection yet, as previously suggested?

2) Connect a voltmeter to the battery posts. Have a helper turn the key to start as you watch the meter while the starter circuit is under load. The voltage should not drop below 10.0v under the load of the starter. This is a poor man's load test of the battery.

 

The P is illuminated.

As for the security system:

A little bit of the car's history. The car's fob has not been properly locking the doors since I bought the car. I mean when I push the lock button, I can hear the doors getting locked but then they get open right away. There is no chirp in the process. I have been leaving the car open all the time. I've had no issue driving the car until now. I have owned the car for about 3 years now.

Funny I have never seen the car with the security alarm activated until now that I have been connecting and disconnecting the battery. The car gets armed at the moment that I connect the battery. I can see the red light flashing and the alarm sounds if I open the door.

This is what I did as you suggested. I connected the battery. The car got armed. I can see the red light flashing. I disarmed the car with the car's fob. I turned the key on to run position (but did not start the car) and the red light did come on solid for about 3 seconds and then it go out.

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I removed the short negative battery cable where it bolts to the body and I cleaned the surface to bare metal. I also cleaned the battery connectors and posts.

I will test your last step tomorrow once I get someone to help me.

I appreciate all the help!

 

Something is strange here. This is like peeling back an onion. We've still got the misfire problem, but that's pretty much secondary until we get the starter to engage normally.

Please let me make sure I understand the situation correctly. The no-start condition is brand new, and only happened after you had disconnected the battery for a misfire fault code reset. Prior to that, you didn't have any starter problems for the three years you've owned the car.

This remote troubleshooting can be kind of tricky and require a lot of back and forth, which takes time. I won't be offended if you just haul the poor car to a shop. I'm not sure of your experience level, tools, financial resources, etc. I have a lot of experience, every tool known to man, but am also exceedingly cheap in my troubleshooting approach. The battery may still be bad, but I hate to say just replace it as a precaution. I have an idea for a quick and easy test of the battery and starter system. I'm still perplexed why the starter won't even crank. I have no idea why. I'd like to determine if there is a fault with the battery, the starter itself, or the connecting cables. I was initially leaning towards a bad cable connection because the problem started right after you had been moving the cables around, but now am not so sure. The other possibility is the starter operation has been inhibited for some reason, still to be determined. That's why I had you check the P/N indicator lights, and the operation of the security system. The door lock/alarm arming doesn't seem to be working properly, but that's not a new problem. And the indicator light for the security system isn't showing any faults that would inhibit the starter. Excuse me while I scratch my head some more.

Plan of attack! The later part of this test sequence will mimic the normal input to control the starter, as if you had turned the key, but bypassing any features that could inhibit the starter:

1) Make sure the transmission in park, and the P is illuminated at the shift lever bezel.

2) Connect a voltmeter directly to the battery posts, not the cable ends. I like to drive a small sheet metal screw into each post for attaching the meter clips. Record the prestart voltage.

3) Since you mentioned having had the battery charged, unless you ran it way back down again, it is probably still sufficiently charged for this next step. Ideally the battery should be fully charged, but I'm trying to work around your present situation. Have a helper turn the key to start. Even though the starter won't engage, watch the battery voltage. It is normal for the battery voltage to drop under the load of the starter. If the voltage only drops a fraction of a volt or not at all, the starter has not received the start command and we can troubleshoot accordingly. If the voltage drops below 10.0V, that tells us the starter has received the start command and the battery is either discharged or in poor condition. In that case, it is time for a new battery.

4) From the above step, if the battery voltage barely drops or not at all - Let's figure out why the starter is not getting the start command. Look at figure 02.1 in this wiring diagram for the starter circuit:


http://www.jagrepair.com/images/Auto...x2062004en.pdf


Turn the ignition off and remove the key. Remove starter control relay R20 from the front power distribution box under the hood. The individual sockets in the panel aren't labeled, but the prongs on the relay should be. You will have to figure out which socket is which by the corresponding labels on the relay. First thing is to check for battery voltage at panel socket #3.

5) Fabricate a pair of test jumpers from paper clips or similar material about the same thickness as the relay prongs. We are going to jump from socket #3 to #5. Don't just stick one jumper between both sockets, as you may get a little spark and the jumper could weld itself in place. Instead, put an individual jumper into each socket, and then touch them together. That way if they weld together, you can easily pull them out of the panel. On the slim chance it gets hot, have a pair of pliers in your back pocket, ready to go. With the key still removed, go ahead the momentarily touch the leads together. This is the same as if the starter relay R20 had been energized by turning the key to start. Obviously the car won't start (key is removed), but the starter should crank. That's all I care about for the moment. If the starter cranks normally, we know the battery, starter, and all connecting cables are good. Then we'd have to figure out why the starter command is missing.

Hope this doesn't sound like too much. This is really just some basics to zip through and shouldn't take long at all.

 

I followed your instructions and the starter got engaged!

Something about the battery: I ended up going to the parts store to buy a new battery. They gave a new one but it read 12.10V. I told them to charge it. They charged it for about 30min. They came back with the battery and told me it was 100% charged. I checked its volts at home and it read 12.33V. My old battery is reading 12.34V!!!. I went ahead and connected the new one just to see what would happen. As I suspected, the car did not turn on and behave just as my old battery (I might return the new one tomorrow).

Then, I connected the old one back to the car. I went ahead and did what you told me. I jumped the relay sockets and the car's starter is engaging. That is good news I hope.

Please be patience with me as I work all day and I am doing all this testing when I am off work at the end of the day.

Thanks for the document you sent! Even though my car is a 2004 model (not 2002) the electrical wiring is still applicable.

I hope you have more suggestions.

Thank you!

 

Sorry I forgot to mention about the results on the other test you suggested.

After making sure the transmission was in park. I connected the voltmeter to the battery posts.

Here are the results:

Voltage with battery disconnected = 12.34v
Voltage with battery connected (car with the KEY NOT TO START) = 12.15v
Voltage with battery connected (car with the KEY TO START) = It initially went to 12.03v and then it settled on 12.08v

Thanks,

 

Okay, making some progress. What we know so far:

1) The battery (new or old) may not be in optimal condition, but is stunningly adequate for our present troubleshooting. It may not hold voltage high enough to keep all those warning messages at bay, but we can worry about those later. Many S-Types with worse batteries have started successfully, even if the dash stayed lit up like a Christmas tree.

2) We also know the starter and all connecting cables are in adequate condition.

This is where I strongly suggest you get an automatic battery charger with at least a ten amp output. (Predictive text on my tablet completed that entire sentence after I started typing "automatic".) I don't know where you're working on the car, perhaps at an apartment or 7-11 parking lot where it would be terribly inconvenient to run an extension cord. But if there's any way you can keep that battery (new or old) fully charged, it may save us a lot of grief. It's just a basic part of electrical troubleshooting, hopefully you can make it happen.

It is kind of a black art to use resting voltage to determine a battery's overall health and state-of-charge (two separate things, BTW). I don't put a lot of stock in those readings, considering them ballpark values only. The preferred 12.6+? That's not really a guarantee all is good, as there are some variables that can give a false high reading. But lowish, such as down around 12.0? Yeah, that's pretty reliable that the battery is nearly discharged and/or has one foot in the grave healthwise. The 12.3ish you've been seeing? Fair to Midland at best. Hence back to my suggestion to have a charger at hand for the most accurate troubleshooting. Remember, no trickle charger, it won't cut it.

More steps you can take:

In the trunk, make sure fuse F3 is good.

At the primary junction box (outboard of US passenger's feet, just forward of front door), make sure fuse F1 is good.

Near the front of the wiring diagrams, page 15 or so, you will find details of these panels showing fuse and relay locations.

Reinstall relay R20 under the hood, where you jumpered across to engage the starter. (For future reference, did you get any sparks?) Place your finger on this really and have a helper briefly turn the key to start. If (big if) this relay receives the command to engage the starter AND energizes accordingly, you will feel a distinct click.

The results of the relay click test will determine the next step.

Good click: The relay's internal electromagnet is good and the start command is present. R20's switching output (what you jumpered) is bad. Replace R20. For confirmation until you can get a new relay, swap R20 with a known-good relay from another system. R6 under the hood is a good guinea pig. It controls high and low speeds for the wipers. Make sure the wipers work on both speeds and then swap R6 and R20.



No click: Either the relay didn't receive the command, or the little electromagnet inside the relay is bad. Test R6 as described above and swap with R20. If still no click at R20, then the start command is absent. That will require more in-depth troubleshooting.

One more tip if no click at R20: Turn the key to the run position. Move the driver's seat all the way back, then forward a few inches. Turn the key off. The seat should stay put. Remove the key and the seat should move fully aft. This is a feature for easy access and will test the "key-in" sensing switch. If this switch has failed and never realized when the key was inserted, it may have confused the security system, but not badly enough to store a fault.

 

Hi Karl,

You're on an excellent logical diagnostic roll as usual, so I really hate to respectfully disagree with such a guru, but since dialectric grease is, by definition, an insulator, it really should not be applied between the contact surfaces of the battery cable and body. It may add considerable electrical resistance to this critical connection.

I would suggest that a better method is to thoroughly clean the surfaces (a brass-bristeled brush and zero-residue electronic cleaner work well without leaving deep scratches that can promote future corrosion), reconnect the cable to the ground stud and snug the nut, then apply dielectric grease on the entire assembly to seal out moisture.

Dielectric grease works acceptably well on conventional light bulb bases because the bayonet pins "scrape" the grease out of the way when the bulb is installed, and lamp circuits aren't terribly sensitive to slightly reduced current. But in a "squashing" connection like the battery cable-to-body ground point, grease may be trapped between the contact surfaces, replacing resistance from corrosion with resistance from grease.

My two cents, for what they're worth.

Keep up the great work!

Cheers,

Don

 

Okay Don, you and me out in the alley, let's go.


The best way I can explain this is how I was taught years ago. Dielectric compound is neither an insulator nor a conductor. It's right in the middle, basically inert. When applied to a connection, it does not block the flow of electricity, especially since it gets pushed aside. You still have the same metal-to-metal contact as if the joint was dry. The only difference is any voids are filled with this inert compound and thus deprived of oxygen, which dramatically blocks the chance of corrosion.

We use dielectric compound extensively in aviation, especially for external antenna connections and other places prone to corrosion. Boat trailer manufacturers use it, packing connectors before crimping to help exclude corrosion from repeated dunkings. I personally have used it on all of my vehicles for about 30 years, with zero problems. I have a tube of Dow DC4 in my tool chest and you would have to pry it from my cold, dead hands to make me stop using it. As fantastic as this stuff is, It also makes a great desert topping.

Before you ask, why not use a conductive compound instead? Wouldn't that make a connection even more reliable, versus an inert compound? In theory yes, but not in practice. Any compound that got in the wrong place would create an unwanted conductive path, either between wires or from a wire to ground. Not good. Inert is better.

About the only way you could screw up using this stuff is packing a sealed multi-pin connector too full, preventing the connector from seating fully.

Searching online for such info is kind of disheartening. Lots of individual opinions on various forums, etc., but precious little from the horse's mouth, i.e. the manufacturers. Here's some info from Loctite, from the Technical Data Sheet for Loctite LB8423:

https://tdsna.henkel.com/NA/UT/HNAUT...%208423-EN.pdf


From the same document:

For connectors and battery terminals:
1. Make sure ignition system is off.
2. Clean surfaces with appropriate cleaner such as LoctiteŽ Pro Strength Parts Cleaner or LoctiteŽ Battery Cleaner.
3. Coat both parts with grease.
4. Reassemble.

 

Hi Karl,

That's a gracious offer but I'm sure you'd kick my old butt in no time!

I'm well aware of the widespread misuse of dielectric grease and the misleading information even from its manufacturers, but like you, I try to be an independent thinker who seeks facts despite "common knowledge" or "conventional wisdom." So I'm all for the intellectual sparring that makes this forum such a great place and helps all of us become more knowledgeable, and I've certainly learned a lot from you.

In lieu of an extended essay, I think these three points will illustrate why I maintain that dielectric grease should be used on the exterior of electrical and electronic connections to protect from moisture and other contamination, but not between conductors:

1. While a dialectric material may have the capacity to store a static electric charge as in a capacitor, it is an insulator that does not conduct direct current. Here's the definition from the Modern Dictionary of Electronics, 7th Edition:





2. Try this experiment: put a blob of dielectric grease like your favored DOW DC4 on a non-conducting surface. Set your ohmmeter to any resistance setting, even 20 megohms. Insert the tips of your probes into the blob from opposite directions and see if you measure any electrical conductivity whatsoever until the probes actually make contact with one another.

3. The fact that you will not measure any conductivity until the probes touch should come as no surprise, because in the Material Data Safety Sheet for DOW DC4 dielectric grease, it is officially called "Dow Corning 4 Electrical Insulating Compound."

Dow Corning 4 Electrical Insulating Compound MSDS

Cheers,

Don

 

Um, Don, I don't believe anybody is allowed to disagree with me. I'm pretty sure it's in the forum by-laws.

 

I just checked, and you're right!

I take it all back!