Jaguar Forum banner
1 - 3 of 3 Posts

· Registered
Joined
·
797 Posts
Discussion Starter · #1 ·
Hey all! I'm cross-posting this here and Jaguarforums.com, as this is probably a fairly obscure topic.

When I bought this car, I requested a vehicle specification from Jaguar. The listing revealed that the car was fitted with an electric engine heater; "ENGINE BLOCK HEATER 230V". Looking at JEPC, it was most likely a 700W Temro heater that heats the engine coolant (no circulation though). Heaters of this type are very common in colder climates, just not on newer cars as they rarely have the intended mounting hole for it on the engine.

As there was no cable to connect the car to a mains socket (Temro cables for European 230V spec are discontinued), I never used the heater. However, last week I had it removed and replaced with a Defa system (similar, but 600W I think), with a Y-piece for an electric interior heater.

The mains socket at my parking spot provides electricity for 2 hours, on a timer. That's enough to raise the coolant temp (checked with OBD2 scanner) some 25-30 °C above ambient temperature.

Unfortunately, if the pre-heated car is started after it has been sitting for more than 8 hours, it throws code P0116:





During this week, I've tested this with various sitting periods, in chronological order:
7h: no error
14h: error
9h: error
8h12m: error
6h15m: no error

My theory is that after sitting for 8 hours of longer, when started the ECU compares coolant temperature with ambient/intake air temperature, and if there's too much of a difference, concludes that the coolant temperature sensor is faulty. I've read that some recent cars have a similar setup, and apparently it's even required by some recent emissions regulations.

This is all quite surprising, as an engine heater is available from the factory. One would think that a heater-equipped car would thus be configured, at the factory, to skip such a test. I tried searching for a similar issue but have found nothing.

Any ideas?
 

· Registered
Joined
·
4,346 Posts
I've never used one of these but I have a German friend who lives and works in Stavanger, his last car had a Webasto preheater system fitted and his current (Mercedes GLC) has some other type of factory-fit system. I'll ask him next week once he's back at work about this.

In the meantime, are you able to test a sitting-period (say 8 or 9 hours) with a shorter pre-heating period? My theory is if you preheat the coolant to a lower temp, will that mean that the temperature difference is back within a range that car will tolerate without showing the error. I'm guessing that the check that throws that error message is calibrated to expect a certain range of temperature differences and the new preheater is raising the coolant temp beyond that.
 

· Registered
Joined
·
797 Posts
Discussion Starter · #3 ·
I've never used one of these but I have a German friend who lives and works in Stavanger, his last car had a Webasto preheater system fitted and his current (Mercedes GLC) has some other type of factory-fit system. I'll ask him next week once he's back at work about this.
I had a Webasto on my Fiat 500, which I could activate from my phone. The phone would also show battery voltage and car interior temperature. It was such a good setup I would've wanted one for the XK, but the installation is very complex, and there is no information available whatsoever on how to get it to work on an X150. There was one horror story of an extremely expensive attempt made in Finland, but in the end they couldn't get it to work.

In the meantime, are you able to test a sitting-period (say 8 or 9 hours) with a shorter pre-heating period? My theory is if you preheat the coolant to a lower temp, will that mean that the temperature difference is back within a range that car will tolerate without showing the error. I'm guessing that the check that throws that error message is calibrated to expect a certain range of temperature differences and the new preheater is raising the coolant temp beyond that.
I'll look into testing that, good point. If that were the case, though, I reckon I'd still rather use it for a longer duration to get the most out of it, and then just clear the code everytime...
 
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top