I am a great technician but this thing has me beat down!!! NO SPARK!!! I have checked the crank signal changed out two known good sensors and have a crank signal, I have fuel pressure, power at injectors and coils. Resistance tested the wires from coils to ECU all good! replaced ECU still no spark! No codes PLEASE HELP!!!! Is there something I am missing here, what does the security system disable????

 

Search the forum for No Spark. I found. A neutral switch cause. They said to try to start it in Neutral and see if that works. Other than that the search has several other causes. good luck.

 

like rick say , on these cars the neural safety switch will allow the motor to crank ,but inhibits spark . make sure the "park" light on the shifter is lite when cranking

 

The linear switch on the side of the shifter was flickering when the P or D or N was illuminated it was cleaned and it does not flicker anymore but still does not start i'm going to try to bypass it . the neutral safety switch thats on the transmission I do not see anywhere, the xkr has a mercedes tranny any help where that is located would be great, I have never been so stumped in my life,

 

this is what i can not find

New Jaguar Vanden Plas XJ8 XJR XK8 XKR Neutral Safety Switch Genuine LJA 6201AD | eBay

 

You may want to shift through this:
Mercedes-Benz 722.6 Transmission FAQ - Mercedes-Benz Forum

Comparing the jtis to the ZF to the 722.6 while the ZF has a service on the range/neutral switch the 722.6 does not, so the implementation is different, I believe it may get the signal through the duel linear switch to the tcm.