When last I wrote my Jaguar XJ8 X308 (AKA Lord Donnington) was starting intermittently. Some mornings it started fine and if I drove off to someplace it wouldn't start when I hopped back in. Sometimes using my jumpstart device would get it to rumble to life again and sometimes even the paddles of life would have no effect and I would just have to wait. Then it would start. That's when I posted about it here and I got a lot of great responses. I checked the engine ground strap, the battery cables, the battery, the alternator, starter, inertia switch, I ruled out the energizer ring (although I have a new part and will probably put it in) and the key transponder. I checked the high capacity fuses under the trunk spare tire cover, the bulkhead battery cables connector-nothing. All are good.

I teach so I tried driving it to school one morning and was idling at a light when I got the warning light in red "Engine Stall" I thought to myself "my engine didn't stall" -and then it stalled. Nothing like a long line of cars behind you when you hit the hazards.The dash warning lights are: Check engine, airbag, Transmission fault, restricted performance, TRAC not available, ATC not available-the usual. Luckily this time it caught and restarted when I cranked it. I drove into the parking lot and put my ELM code reader into my OBDII port. Usually I get cam and crank position sensor codes. This time here's what came up:

P1797 (CAN issues...)

I read a thread where a guy talked about the wiring from the transmission pan to the TCM. The multi plug that you can see by crawling under the driver door and looking at the back of the transmission pan. I think it connects to the transmission valve bodies and on to the TCM and to the ECM. The guy said tranny fluid leaked and upset the harness. Mine looks completely dry.

So what other solutions can I try to get P1797 solved? Lord Donnington won't even start after a long night of sleep anymore. No crank at all. Everything lights and up my seats slide forward in anticipation of a long drive but it's a drive to nowhere now.

Why won't my car start? Or stay running when it does start?

I would appreciate any insights anyone may have. I don't have a dedicated older Jag shop here in Savannah. The only Jag shop in Savannah won't look at my XJ8. Its' too old for them. I miss Steve's Jaguar in LA...


Thanks,

Scott

Savannah,GA

 

Have you tried resetting the fuel inertia switch I had same problems starting no problems since in passenger foot well worthwhile checking it out could be an easy fix

 

Thanks, but I checked that and still nothing..

-Lord Donnington

 

From what I’ve read with others, it’s often the harness that goes into the Transmission. You said yours is completely dry, but I would remove it, clean with electronics cleaner and reinstall. Do a hard reset.

If the Canbus fault code can’t be cleared with a hard reset, you need IDS to try to clear it.

 

If I was in your position, I would start by disconnecting and reconnecting modules, especially the instrument pack. As silly as it sounds, I’ve fixed a few cars that way and chalked it up to micro corrosion between the connector and whatever module I’m aiming for.

 

Reading your thread I figured I better quickly do a write-up of the wisdom I gained today, when working on the engine of my X-Type.
I found something worrying, which could possibly be the reason for your problems (a CAN bus issue is an electrical issue in my book).
This problem is not limited to X-Type or X308, it is possibly an issue with all cars...:

https://www.jaguarforums.com/forum/x...4/#post2638592

 

I had these codes on all three of my 200o VDP cars as well. When you got the code, was there any other description in the read out area? I my case I would get the codes but finally it would display "Instrument Cluster Failure". Swapping the cluster resolved it every time.
I am attaching a block diagram of the CAN bus in case you don't have it.

 

David we like the same color XJ's. You may be on to something. Every once in a while when I turn on the instrument cluster lights I only get a partially lit cluster. The only instruments that are lit are the fuel and temp gauges. The next night everything would be fine. Last night I got into the Jaguar and used my starter jumper and the car fired right up. The dash was also fully illuminated. So I will take out the cluster and spray electronic cleaner onto the plug and see if that helps. Thanks for the reply.

 

I will try that next. Thank you for the reply.

 

So last night I went out and measured the battery voltage. 12.24. I tried starting the car and nothing. No crank just clicks and the sound of the fuel pump. I used my jumper and it started right up. I let it idle until the car was warm-about the time it took to start the album Born to Run on the CD changer and finish with "She's the One". I shut it off and then turned the key again and she started right up.

So not the exciter ring.
I will proceed by disconnecting my instrument cluster and cleaning the connection
I will check the ohms at the CAN connections: ABS-TCM-ECM-gear select (I did install a new micro switch in there a month ago...)-Instrument pack-OBD connector and see what I find. Should it be a reading of 60 ohms at each junction point?
Then move to disconnecting all of the modules I can find: Security, body processor, ECM. TCM and cleaning.
Then I will disconnect and clean the multi-plug coming out of the transmission.

See where that all leads me.

Thanks for the suggestions everyone.

I miss driving my car especially with its new leather interior.

 

Fascinating, Peter. Thanks for the heads up on this issue.

 

@ Lord: While the voltage reading 12.24V sounds OK, I find it worrying that you cannot start your car with that battery, but straight after connecting the jumper it starts...
This actually tells me that you need a new battery to solve your problems. Some batteries can be damaged in a way so that that display an OK voltage, but if you want to start the car, the required AMPS are just not being delivered. Batteries are a tricky thing and it is a science for itself to determine how charged up any battery actually is. After you let your car run for a while, the alternator charged up the battery, and with that charge still in the battery you could start your car again. But if your battery is faulty, that "power" will disappear into thin air and next time you want to start again a while later you will be buggered again.

I general, I also recommend that every Jaguar owner has a CTEK battery charger that delivers 5A or more. I have two (5A and 15A) and I have them in permanent use: With solar on the roof I connect them to the batteries of my "fleet" whenever the sun shines. I can't drive all my cars, so that would quickly destroy the batteries and replacing them all the time would be quite expensive.

A "partially lit cluster" - as you describe it - or a dimly lit cluster are actually good indicators for a buggered battery.

Additionally I would like to throw out there: If you measure 12.24V that does not necessarily mean that you have 12.24V - your multimeter could be buggered, or at the very least the battery in your multimeter might be close to being empty, which can easily result in wrong measurements, especially higher measurements. As far as I know multimeters "compare" their own voltage supply with what they are supposed to measure, and with the own voltage supply being "off", the measurement will be off.

 

Yes, the battery is the first suspect here.

 

Peter,
I charged up my battery on Thursday. It read 12.61v without the engine running. It started right up. I let the car sit until Saturday and it read 12.34v. It also boomed to life when I turned the key.

I will see what it reads tomorrow.

Thanks,

Scott

 

Good, Scott.
Regarding charging: A CTEK battery charger is really better for the battery (intelligent charging).
Some of them even have a "reconditioning" mode.

Regarding battery discharge: We do not know yet, if your battery is still fit for the job, i.e. if it holds the charge long enough.
Another thing you could check is, is what the quiescent current on your car is, i.e. how much current the car draws from the battery when parked and find some figures of what is normal. Note that some systems are probably on a time delay after parking, i.e. the measurement after 30 min (to be sure) would be more relevant comparted to directly after parking the car.'

How to measure the current: Don't do it with the engine running (or starting) - current to high, but:
Connect the leads of your multimeter differently compared to when measuring voltage: It's a different input connection: the one for 10A. And set it to 10A measuring mode.
Disconnect one lead of your battery and connect the battery instead to that lead with the multimeter inbetween. CHeck the current draw.

When done, do not forget to plug the leads of your your multimeter back to Voltage measurement - failure to do so will kill your multimeter next time you measure a voltage with it.

 

Peter
I don't seem to have a 10Amp measuring mode on my multimeter. But I measured the charge this morning and the battery was 12.64V. It started right up. Boomed to life. I shut it down and then started it again and it started up. No hesitation. Tonight I started it up and parked it on the street in anticipation of a long drive/road test. It wouldn't start. Key just turned. The wiper blade went across the windshield once. I measured the battery and it was 12.31V. I jumped it with my starter thing and it slowly cranked and then caught. I pulled it back into the driveway. So why did my wiper activate when I tried to start the car? I seem to remember reading about someone else who had the mysterious one wiper swipe and then nothing.

I just don't know what is going on. The car should start at 12.3V. It starts fine at 12.61V. New battery?

-Scott

 

open circuit voltage is pointless…load test the battery

if it’s good check the main power cable at the fake firewall. if it’s loose current draw goes way up and it will only start on a jumper or a fully charged battery

 

I will need someone else to start the car so I can watch the multimeter in the trunk, right? What am I watching for on the multimeter? A drop below 12V?
When I connect my ELM OBDII reader it shows the voltage in real time. Will that give me a way to load test the battery? I guess I don't know how to load test a battery...

Scott

 

Thanks. The false bulkhead battery cables were taken apart, cleaned and put back snug.

 

If you didn’t touch the wiper arm at the time it swept the windshield, you might be looking at a failing BPM. I’ve seen that one before.