Hi all,

I'm having trouble with my 2004 S-Type 2.5L. The car is cranking but won't start. I checked everything I could, now I'm getting desperate.
- battery voltage is OK,
- rail fuel pressure is OK
- PATS is OK
The car stood for quite a time but did start and run a few weeks ago.
I checked the voltage on the ingnition coils and there's 2.5V on the red wire and 5V on the yellow (seems odd that there is no 12V!?). I attached also the full DTC list from SDD.
Any ideas what can be wrong?

 

Does this red wire also have a white dash, dots, or similar marking?

Take a look at your wiring diagram here, near the top of the page:

JagRepair.com - Jaguar Repair Information Resource


Scroll to figure 03.2 to see the six coils. At each coil, the wire labeled RW (Red base with secondary white markings) should have battery voltage with the ignition on. If you're only seeing 2.5V, it seems you're hot on the trail.

You can follow common power to the coils via the "118E" legend inside a circle, which leads you to figure 01.7. There you will see that same "118E" legend (and thus the coils) receives power when relay R3 (in the front power distribution box) is energized and the output contacts close. Also note fuse F19 in the circuit, so check that for continuity.

To test if relay R3 is receiving the command to energize, place your finger on the relay. Have a helper turn the ignition key on and off. You should feel the relay click each cycle. Other relays in the vicinity may also click at the same time, so make sure any click you feel is coming from R2.

If you feel R3 clicking as commanded, also test relay R2. It is piggybacked onto the output from relay R3, which you just tested. If R2 clicks at the same time as R3, that means R3 is working properly. The next step would be to check for voltage at fuse F19 when the key is on.

There are more items we can check, but these simple tests should put you on the right path for further testing if needed.

 

Did you use an OBDII scanner to read out the codes?

Actually...: On that front:
I had a little bit of spare time today and I used it to check out my scanner collection:
1. Since ages I have an ridiculously expensive but pretty rubbish scanner (XTOOLS). I annoys me these days, because the scanner-software on that tablet disappears from time to time and this thing asks me to buy new software for a fortune - that's not going to happen - and then, a few days later the software return magically. This thing had cost me about AUD$500.
2. Just tested, and tested OK: ANCEL AD310 from Aliexpress - a little thing for about AUD$15.
3. A little OSBII plug, which connects to my mobile via blue tooth. The plug's cost were below AUD$10. I was already about to give up, but then I found an operational and free app for it. It cost me quite of bit of time today to connect it all. I had to pair the bluetooth connection, and it asked me for a pin for the plug. I did not have one. But the program told me, that the pin is probably 0000 or 1234 - well, it was 1234. Just like in "SPACEBALLS"...
I have currently 2 faults on my x-Type, and all 3 scanners displayed the same 2 faults, and those 2 only.

Back to your "no-start": My 3 cents worth: Change your fuel filter! This is a good thing anyway, and it might even be the cause of your problems.
I use the brand WIX for fuel filters.

 

Peter, there's an important caveat for using OBD fault codes to troubleshoot a no-start condition. The primary function of the OBD system is to monitor for excessive emissions. In most situations, you have to complete one or two drive cycles before a fault is reported.

A no-start condition? That's somewhat of a different critter. Even though the computer is likely well aware why the engine won't start, that's not technically an emissions-related fault and the computer is not programmed to tell us mere mortals. Some dealer-level equipment can read such data, but that information is not available to us via normal OBD channels.

I liken this situation to getting in the wrong line at the Department of Motor Vehicles. You might be there to renew your vehicle registration, but unknowingly got in the line for title transfers. Even though the lady behind the counter has access to the entire computer system, the only way to complete your transaction is to get in the correct line.

 

Thanks alot Karl. It was the R2 relay, I changed it and now everthing works just fine.