Hi guys,
I've barely driven my car (X-Type 2.0 diesel sport) for two weeks and this code has come up P1638. I have gone through the wiring system twice and can't see any wiring problems, all connectors are rust free and no disconnections.
Can someone please give me an idea on what to do. Message ' communication failure ' came up on the navigator screen sometime ago tho and the fault code B2141... No jaguar dealers here so I'm stuck. Please can someone give me some insight...

 

Hope this helps.

Decided to attach the the section from the manual that should shed some light.

 

Thanks for the document Paul.. This document definitely helped.We have checked the whole wiring system and found out the problem was that the power supply to the ECM was not functioning at all... Our only challenge now is finding the cable that supplies power to the ECM... I hope anyone can help me with some info on this if at all there is... Thanks guys

 

There are a number of supplies to your ECM. All are ignition switched.

Pins 3, 4 and 5, all White/Green wires, fed through Fuse 21, 15A in the Engine Compartment Fuse Box.

Pin 18, Green/Blue wire and Pin 37, Green/Orange wire, though Fuse 31, 15A in the Glove Box Fuse panel.

The Pin 18 wire is also fed through the Inertia Switch, so check that hasn't tripped. It's located in a hole in the driver's side footwell, outboard trim panel.

 

sounds weird but pull your ecm out. You will need a 5 star torx. Unplug the wiring and pull out your ecm. Then connect it back in the engine bay and see if it starts. I had an issue after swaping out an engine.
Worth a shot. If it starts unplug and re set it back in its spot under the dash.

 

Any update on this. Currently having same p1638 code. And car doesnt crank