I took the white car (Roger) (the Nice one) out for a spin just now. It's Feb. 12. Mid 40s F. Roads are dry . Of course I expected an uneventful drive but I can't help but notice that damned light on Again! This time it's FF 14. Should be a simple fix, but Really?!??!? I hope this isn't an indication for the coming season.

 

Hi Jerry,

I feel your pain. Too often it seems like a Jaguar without a malfunction is a mythical beast.

Maybe the CTS just has some corrosion on its electrical connector or the harness wiring or connector is deteriorating from heat, but if you don't see anything obvious, try cleaning the ground points used by the ECM (the two on the intake manifold and the one on the firewall behind the cylinder head).

Worst case, the sensors were used on lots of cars so they are common and cheap. If you decide you need a new one, get one with an integrated metal hex instead of the newer style with the hex molded into the plastic body. I once ordered one pictured with the brass hex, but received one with the plastic hex which broke loose from the sensor body before it was tight enough to seal and leaked like crazy.

Also, remember that there are two coolant temp sensors: the two-wire one with the Bosch EV1 connector feeds the ECM, but the one-wire sensor with the spade terminal is the sender for the temp gauge in the instrument cluster. Sellers tend to call them both coolant temperature sensors.

Please keep us informed once you sort it out.

Cheers,

Don

 

Today, a full month later I finally got around to changing the coolant sensor. I also changed the temp sender while I was right there. But misfortune dogged me all day, and the engine light is still on and still ff14. I tried the instrument panel reset but to no avail. In the 92 car its fuse 6 in the center fuse box. This saga continues.....
Lately I have also been digging into the S-type and today managed to snap a couple of "important" bolts despite liberal and repeated P Blaster applications over several days. We shall see how that comes out.

 

I had changed out my coolant temp sensor on my '88 but the problem persisted. It turned out the wiring near the connector was a bit frayed and probably shorting it out. I replaced the sensor connector and a few inches of wiring going up to it and that solved the problem. Check your wiring near that connector and replace it if it looks deteriorated.

 

Thanks, Ive just been poking around on "other" sites and had come to that conclusion. The connector isn't as pretty as it used to be and I am considering deleting it at least as a test. Possibly tomorrow evening if I don't get suckered into the 66 differential on my workbench.

 

Today I removed the connector at the sensor leaving only the tips of the wires. These wire ends seem designed to fail. I crimped them back tight and put them on their respective terminals but got No improvement. I also pulled them both with motor running. There was a noticeable but not dangerous increase in RPMs which went away when I reinstalled the wires. This makes it seem to me that the wires are intact. Stay tuned for the next episode when Alice awakes from her delirium and all is Magically well again!

 

In my case the connector itself looked fine but the wires leading up to the connector for about 3-4 inches back had cracked insulation on partial bare wire. I would get an intermittent code sometimes and other times I wouldn't. I replaced the sensor and no change. Then one day while it was running I jiggled the wire a bit and noticed the code reappear. Replaced that few inches of wiring and the connector,heat shrinked it all up,and everything has been well since. You can do an Ohm test across the two terminals to see if the sensor is working. If I recall,when the engine is cold the reading across the two terminals is around 450 ohms and when it's warming up it starts to drop. I think it reads somewhere around 250-325 ohms when the engine is fully warmed.

 

On my car the wiring harness is perhaps not fresh from the factory, but it IS uncut and un messed with so I was Really Really reluctant to cut it up. This beside the fact that the wires don't "seem" to be bent, creased or otherwise likely to be broken. I replaced both sensors since I was there and did the fuse 6 reset of the instrument panel. The light remained on. Today I finally got back to it. I got good voltage readings off the sensor and decided to disconnect the battery. This seems to have worked. I ran the car in the garage up to operating temp with no light. I don't want to drive it today as it's wet out and I doubt the roads are free of salt yet.
I have a lot of parts to start putting the rear end of the S-type back together and could do that, but in the interim the Moneyfunnel has got its ff44 code back along with a rather nasty oil leak somewhere off the upper rear parts of the motor. Jaguars are so cool!