I get this intermittently in a '95 4.0 xjs.

After sifting the wiring harness diagrams I located the reference on the GEMS ECU page for something called Model Year 1995.25. But this doesn't make it easy to locate.

I already swapped the Crank Position Sensor, that's something different appearantly.

Any thoughts?
Anyone know where the heck I can find this thing? It's not diagrammed to the vehicle anywhere I can find in the wiring pages.

 

Really, if anyone knows where the engine speed transducer on the AJ16 is located please chime in. I'm reasonably certain it's not the road speed transducer in the differential (final drive) and I'm also reasonably certain it's not the crank position sensor. On the electrical plan there's a separate ECU input line for it on the GEMS ecu but the documentation for that revision is abridged and it does not show a component layout for the wiring harness including that device.

I've poked around the bell housing since I've seen it referred to as a hall effect sensor similar to the crank position sensor that picks up off the flywheel.

I've looked suspiciously at this device:

http://celestialpower.biz/jaguar/IMG_0046.jpg

Can anyone tell me what that is?

 

OK, that seems to be the Cam Position Sensor. So still no Engine Speed Sensor though that would appear to provide a suitable signal.

 

I got it now I think. Engine speed from the ECU is a ~signal~ that informs the dashboard tach and transmission ECU, not an input. Is that completely wrong?

 

F*** it. I just went and bought a WDS. Hopefully that'll take some of the guess work out of this.

If nothing else it'll be a crucial tool for the do-it-yourselfer to keep my jag alive in the coming decades.

Really, I sure would appreciate the voice of experience on this issue.