Greetings Jagsters,

2009 XF SV8 (4.2 s/c V8)
I discovered that my coolant level sensor is bypassed by a resistor and tape. I'm assuming someone was trying to hide the "Coolant level low" error.
I replaced the coolant level sensor and now I have the coolant level low error
Then I bought and replaced the coolant reservoir with the new floating part inside and flushed the coolant with the right mixture.


I still have the darn error on the cluster. Car runs and drives extremely well. No check engine light. All I have left is to solve this stupid issue.
Any ideas guys? My mechanic thinks its electrically related and he's waiting for a diagram from Jag but none of us is sure about the issue really.


Thoughts?

 

If you put the resistor back in does the error go away?

 

If you look I suspect the diagrams are on here, free for download.

 

It does not surprisingly so!

 

I wonder if the resistor patch wasn't appropriate and damaged some electronics

Have you tried power cycling the electronics? Disconnect battery for a couple of minutes and reconnect again?

 

Attachment.

 

As far as I know, the float sensor is a make or break switch, simply connecting the two terminals together should make the circuit and turn off the warning. In your post you said they bypassed this with a resistor, however that in itself might be a problem if the resistance is too high it might also look like an open circuit to the electronics I would have thought it wouldn't need any resistance to make the cluster say its ok. I'd guess that sensor would "make" when the coolant is at a sufficient level, this would be a failsafe design so that is anything went wrong and the circuit failed it would produce a warning on the dash. If its still illumined when the terminals are jumped then maybe there is a fault somewhere else. I'd try a power cycle of the electronics, and if that doesn't fix it then there's a fault somewhere, the sensor goes directly to the instrument panel, so my next guess would be to pull the connector from the back of it and check the resistance with the jumper in as you might have a break in the cable somewhere.

I've got an old tank in the back of the garage somewhere. I'll see if I can find it and test how the sensor works.

 

Check that the float actually floats
https://www.jaguarforums.com/forum/x...2/#post1991901

and this video shows the importance of correct coolant mix.

I posted the diagram pdf for the repair tech if needed, but really if the plug is shorted and the error goes away, doesn't that mean that the cluster is sending a signal? Really puzzling.

And just so you know, the old 4.2 will give you a separate overheating warning if the engine is actually too hot.

 

That was I was wondering, Emms seemed to be saying that bridging the pins doesn't seem to make the error go away anymore. If shorting the pins made the error come and go then its either the sensor, float or mixture.