I have a situation with a no start condition. This is the thread a while back that gives the info on what had happened, https://www.jaguarforums.com/forum/x...h-help-252034/

At this point the engine cranks. I have fuel pressure. It seems I have no spark. The main code I get is U1135. I only have one key so I can't try a different key. If the key was not recognized, would the engine crank and the fuel pump function?

I replaced all relays pertaining to the ignition coils and checked for bad fuses. One fuse was blown and I replaced it with no change. Battery is on a trickle charger and I tried a hard reset with no change. Any thoughts?

 

No.

You reported several codes previously: P1260, C1155, U1135, U1041, and P20EE. I guess the P1260 has gone away since the car cranks?

The others are odd:
C1155 is an ABS issue
P20EE not in the DTC list, but seems to be emissions-related
U1041 and U1135 I can't find either. Searches show a variety of possibilities.

If you definitely have spark, are the injectors firing?

I know this has been haunting you for a long time now. Any other clues - however unrelated they may appear?

 

Hi and thanks for the reply. I got a new Autel scanner and used it to clear all the codes. The ones listed are what came back after trying to start. Even with the P1260 the car always cranked, but that code no longer comes back. Now there is a no crack, no start situation. The other codes for ABS, etc I think are spurious and maybe not related. Unfortunately, because this has been such a long ongoing issue, and because I love the car, I'm looking into buying a running XK8 to transfer the engine, ECU and security modules into mine. Since I only have one key, if the problem is the key not being recognized, I would have to have the car towed to a Jaguar dealer, pay to have the key plus an extra reprogrammed, and If this was successful, still not have running car. Not sure what to do.

 

Bigjohns55.....
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Billy Clyde @ Cinco Ranch

 

I would check the wiring diagram around the ignition switch and locate this DD reference. The words makes it sound like the BPM is unable to determine the key position.

Could also be the SCP bus altogether. Again, check the wiring diagram for what is attached to the driver door module and see if you can get data values from your scanner, proving/disproving the SCP bus works. The wiring diagram has a topology of the various modules and their data bus. Check what else is on SCP and see if they work (get data values on the scanner). To my knowledge, if a control module has any type of input, there has to be a data message with the value of that input that a scanner can read.

Best of luck, keep us posted.

 

I should have been more specific about the two U-codes. They are not present in any documentation I can find until 2003. I guess if they are repeatedly thrown for you that they must have been implemented sooner (when?) but didn't find their way into the earlier DTC lists? Certainly not in 2000 information I have. I didn't want to post something I wasn't sure about.

U1041 shows there as 'Vehicle speed SCP message invalid', which is not directly relevant other than an indication of something potentially amiss on the SCP bus. It appears that this code can be thrown by four different modules.

U1135 is more relevant as fmertz notes above, and I think you can ignore C1155.


I'm not clear whether you have no crank, or crank no start?

 

I had crank but no start. Now I have no crank.

 

Thanks. I'll look into this tomorrow

 

I'll be making a few calls to see if this is possible. I've found companies to cut the key but don't know if they can/will do the programming.

 

You could try jumping the starter motor relay pins 3 & 5 to eliminate/incriminate everything downstream from there while you're pursuing the ignition switch stuff. Check also F5 (10A) in the engine compartment fuse box.

Is the P1260 still cleared?

 

I had a great conversation with Gus over the phone. Thank you Gus. You are very kind and informative. I did have the battery load tested and it is in perfect condition, 12.6v. I then checked all fuses and as Michaelh pointed out above, fuse # 5 in the engine compartment was blown. I replaced that fuse and tried to start. Voila, it cranked and actually started for 2 seconds and then stalled. The no crank problem is solved. Now I'm back to the same problem as befoe of crank but no start. I will start as Gus mentioned, checking each cylinder to see if it's getting a signal at the coil and also making sure the key exciter ring is working. I checked the fuel pressure and it seems to be perfect at 41psi with key on. After 1 hour it bleed down to 30psi so it seems to be fine. So much more to do. Thanks to everyone for helping. I'll definitely continue to need it.

 

Progress. Always good.

Is the start - run - stall cycle repeatable immediately, or do you have to wait a while?

Does it run for 2 seconds, or could it be 5? (There is a logic to my thinking, honestly.)

 

Yes, progress is good It only started the first time I tried after changing the fuse. It ran for about 2 seconds and died. Now it cranks but no start. I now have another question as I'm doing some electrical checks. Using my test light, I was checking all the relays for power. The relays in the engine compartment box, left, all show signal (test light shows 12v on the control and power side). This is without the key. The relays next to the engine ECM show no power. Those relays include ignition coils and fuel injectors. Should there be power at that box with the engine not running? I tried it with the key out and key in run position.

 

I think I may need to check the high power protection module in the trunk for problems.

 

The relays in the engine compartment fusebox should have +12V at their power feed always, irrespective of key position. All bar the front fog relay (that has ignition switched coil power) should have +12V always at the coil feed.

Engine management fusebox. Relay power is +12V always via fuses.

The injector relay coil power feed is via F5 (10A) in the engine compartment fusebox, but you've checked/replaced that fuse?

The ECM controls power to much of the engine managment stuff via the engine management fusebox relay.
If you have no coil +12V on the ignition coil relay, it's worth checking first F14 (10A) in the engine management fusebox, and then that there is power elsewhere:- e.g. a/c compressor relay coil, , O2S heater relay coil, MAFS whatever is easiest to get to).

The Electrical Guide isn't the easiest to follow tracing this stuff through A twin-screen PC setup would help...

Hope this makes sense!

 

Thank you, it makes perfect sense. I'll be looking into this today and tomorrow and let you know how it goes.

 

Ok. I have power to all relays. Now when I start the car, it runs for about 2 seconds and stalls. Fuse #18 on the right side engine fuse box blows each time (10 amp). It's listed as the ignition coil fuse. Not sure why it blows on each start.

 

OK - that fuse only feeds the ignition coils via the relay. If it doesn't blow with with the ignition at the run position (engine stopped), it implies a short or very low resistance on at least one of the ignition coils, or possibly the wiring.

Can you do a resistance check between pins 3 and 4 on each of the coils to see if one is markedly different?

 

The fuse is blowing for a reason. Check all the leads to all 8 coilpccks. If all is good you need to check all the coilpacks by doing a continuity test. Now they may vary so documenting each reading may indicate the one that is in trouble.

Gus
JagRepair.com - Jaguar Repair Information Resource

 

The fuse doesn't blow with key on. With key on, there is power on all of the coil wires. I next have to check the resistance on each coil. I'll do that tomorrow. I have some new, extra coils to try if any show a problem.