I'd really appreciate some insight beyond what I've been able to find searching the forums.

Car is 2004 V8 VDP and it just turned 100K this past week. Has been running beautifully without any issues. Went out to garage to use car, but key wouldn't initiate starter motor.

Display scrolls Gearbox Fault/DSC not available/Parking Brake Fault

J-Gate won't move out of park.

I know these cars are sensitive to a weak battery, so I first put it on a charger which produced no change. The car is just about due for a new battery, so I installed a replacement knowing it likely wouldn't fix everything, but it would eliminate it as a cause.

It has been raining here (for a change!) and there was some discussion here of water damage to ECUs and I checked the area where the cabin filter is located, but it is dry and the drain is clear. Not sure if there is other ways water can reach the ECU, and not sure exactly how to access the ECU to check.

This car has been so trouble free that I just don't know it as well as I know my other Jags, so any insight would be greatly appreciated.

Thanks

 

I would say 100% battery related... A replacement should fix all your issues. You may want to consider a trans pan/fluid/sleeve change if it hasn't been done already.

 

The following is copied from the service manual for the 2003.5 through 2004 model year XJ8's. The first covers things opt check excluding the starter motor itself and the second section is just the starter motor.

You've already replaced the battery and if you don't think it's fully charged (12.8 - 12.9 bolts static test with multi-meter) then be sure to get it fully charged as you're correct about a failing battery causing all kinds of trouble..

I'm betting on too high a resistance between the battery and the starter so check the input side of the starter for loose or corroded connection as well as the ground side. In fact do this at both the starter and the solenoid. There's also the possibility however slim that the wiring carrying the voltage from the battery to the starter has internal resistance from age alone as that used to be a problem with Volkswagens as well. You could check that with the Ohms setting on a multi-meter as well




Symptom

The engine does
not crank (starter
motor does not
turn)


Possible Cause(s)


Gear selector not in P or N
position (vehicles with
automatic transmission)
Battery
Harness/Connectors
Starter motor
Starter relay
Ignition switch
Transmission control module
(TCM)
Engine control module (ECM)
Engine seized


Action


Make sure the gear selector is in the P or N
position and correctly adjusted.
Selector Lever Cable Adjustment (44.15.07)
Check the battery condition and state of
charge.
Battery Check the starter motor and harness,
GO to Pinpoint Test G557182p1.
Check the starter relay and circuits. GO to
Pinpoint Test G557182p2.
Check that the engine turns.


Symptom


The engine does
not crank (starter
motor does turn)


Possible Cause(s)


Starter motor fitment
Starter motor
Flywheel/Drive plate ring
gear


Action


Check the starter motor fitment (fasteners
tight, starter motor square to engine, etc).
Check the flywheel/drive plate ring gear teeth
for damage, foreign objects, etc.

 

The gear selector cable can come free at the gearbox end and confuse the system. However, it may be best to get the codes read and a Jaguar expert assess the possible fault from those.

 

I'm just going to throw out an idea here, so please humor me...


Try the other key. Assuming you have two of them.

 

Although it was a earlier model, this sounds similar to a condition that I had on our 97 XJ6L when the bettery got low. The alarm system somehow was set which prevented movement of the gear selector and starting of the car. My independent mechanic diagnosed and reset the system although he thought there was a sequence of using the key in the door which would also reset the system. Might be worth a consideration.

Good luck,
Jim

 

Thanks for all the replies.

It looks like I've resolved the issue. I did a couple of things, one I put the new battery on the charger overnight just to make certain it was fully charged, but that alone didn't fix it.

I checked the gear cable per Fraser's suggestion, which was easier said than done given that the car was rendered a 4700 lbs brick in my garage and didn't have room to use a floor jack. I rigged my iphone on a short aluminum pole to do the inspection for me by taking a video and using the flash as light. The cable was in place, so that wasn't it.

I found searching the forum that the grounding (earth) points can be problematic, particularly the three near the radiator. I removed the cap nuts to clean all the contacts, and even though I was careful not to use too much torque because the stud/nuts are aluminum one of them snapped off as soon as I went to loosen it.

Once I stopped using expletives, I headed to the hardware store, and got an aluminum bolt and couple of nuts. I drilled a new hole, removed the paint to create a clean contact, and created a new grounding point.

The first time I tried the key nothing. Second time, it fired right up. Test drove it, all the prior reported fault codes displayed. Next time I started the car, it asked me to set the park brake, and all faults stopped being displayed.

Seems to drive without issue now.

 

When in acts up again in the future try this...

https://www.jaguarforums.com/forum/x...t-saga-112925/

 

Went to drive the car this am, and it is back to the prior state.

I put a digital meter on the battery and it reads 12.63 volts. So I've disconnected the battery and will retest it later to see if the new battery is defective and won't hold a sufficient charge.

If that tests OK, then I'll put it on the charger and see if it returns to an operating state where I can test if the alternator is charging properly. I guess the 3rd possibility is some kind of load draining the battery overnight, which would be the most difficult to pinpoint.

[sigh] Any ideas or assistance would be appreciated

 

So it was the front earthing points, The one unresolved design fault with these cars. Of course the owners resolve them, but Jaguar never did !

 

It fell back into Brick Mode this morning...

 

At least 12.63 is a good value so battery should be OK.

 

I read through this thread twice, no mention of DTC's? Nobody read the codes? Might be something showing which points in the right direction...

 

Perhaps I had falsely assumed that the low battery was sending so many false codes that there was little point in reading them. I haven't had time to work on the car, but hopefully will be able to read the codes later today.

 

[sigh] My ODBII tool is/was an Autotap USB interface to a pc, however I no longer have a windows laptop. I now have a MacBook Pro, and I couldn't successfully get Autotap to connect to the car using Wine, and I don't have a valid Windows license to run Windows on my Mac.

So I borrowed my neighbors scan tool, which is the Innova 3020 and it attempts to "read" and eventually returns "error".

As previously stated, I'm much more familiar with my '90 XJS and the '95 VDP, does the '04 require the dealer diagnostic software to read the DTCs?

Since the car is a brick stuck in my garage (it won't shift out of park) I can't just swing by somewhere and have the codes read.

Guidance is appreciated.

 

You can use a cheap tool like a Bluetooth or WiFi elm327 and then a smartphone OBD app. Torque lite is free.

Older tools just don't always talk the new protocol but the above are so cheap who cares!

 

Any OB II reader can read the all federally required codes which are listed under the heading of "P" in both OBD & EOBD (extended OBD).


There appear to be at least 4 "P" codes for a direct starter problem. They are, in order, P0512 (2 variations depending on model year), P616, & P617 (2 variations depending on model year. They all deal with either the starter or starter relay getting either too high a voltage or too low a voltage. You could use a good digital multimeter to get a reading while someone turns the key to start.............VERY CAREFULLY

There are of course the other electronic modules as well as mechanical issues that I listed earlier as proximate causes according to the service manual with reference to your problem.

 

An after thought. You might be able to get your local Advance Auto or whomever to do a quick OBD scan for you for free with their scanner which should be a step up from the basic unit

 

I've been trying to pull the DTCs with no luck. I've borrowed 3 different scanners to no avail. Just received today the following:

ELM327 WiFi OBD2 Car Diagnostics Scanner Code Reader for iPhone iOS and Android | eBay

Tried connecting with two different apps on my iphone, as well as two apps on my macbook. One app, OBD Auto Doctor, has connection status report with these results:

connects to wifi at 192.168.0.10:35000
detects ELM327 v2.1 interface
detects ODBII by elm329@gmail.com scantool
failed to connect to ECU

I've tried the usual, confirming to soundness of the plug-in, making sure the key is on, etc. Am I missing something obvious?

 

Sounds like a fault at the socket or between it and the rest of the car. Blown fuse? Bad wiring? Etc.

Er.... you need the ignition on / engine on to enable the socket on most cars. Maybe that's the problem?