Hi Guys
Grateful for any advice

2008 2.3 Ducato (Chausson motorhome)

At start-up (hot or cold) I'm getting a 'radiator fluid temperature exceeded, turn off engine' message on the dash
Engine isn't running hot, guage never goes beyond halfway & no error codes recorded.
Local garage says just ignore it.

Any ideas?

Hi Nigel

As far as I'm aware, there is just one engine coolant temperature sensor (CTS) which connects via 2 wires to the Engine Control Unit. The information is used by the ECU, and also passed on to the Instrument Panel for the Temperature Gauge and Temperature Warning.

However, it doesn't sound like the CTS is the problem, given that the temperature gauge is working OK. So it could be a fault within the instrument panel electronics. In this case ignoring it would seem to be the cheapest option !


If you want to check the CTS and its wiring anyway, it sits in the main coolant circuit at the front left (as you look at it) side of the engine, near the inlet manifold. You may need to move the large air hose to get to it.

That's brill Anthony, I'll check the CTS wiring.
Many thanks for your help

It may be worth checking what the battery volts drop to whilst starting. A google of your complaint brings up several hits where the battery or wiring was to blame.
https://www.fiatforum.com/grande-pu...id-temperature-anyone-know-exact-problem.html

Building on Rayc's suggestion above, is it possible that the fault described by Nigel is caused the infamous engine earth strap?

The standard recommendation for eliminating the engine earth strap, is to connect a jump lead between the battery negative, or a sound earth point on the chassis, and an engine lifting lug, or similar clean point on the engine.

Thanks guys for the above. I can offer a little more info if that helps.
I've only had the motorhome for a month or so and covered approx 600 trouble free miles.

I have replaced the earth strap as I'd heard the original ones could cause issues.
Battery is less than a year old and shows green in the window although I haven't tested it.

Van is fitted with a Toad alarm/immobiliser & previous owner said to start it :-
Insert key & turn ignition on.
Press button on the Toad fob (to disable immob?)
Start engine

I get the high coolant temp warning only after I have pressed the Toad & before I crank the motor?
Thanks again

Hi Nigel

There is a possibility that the immobiliser part of the Toad is causing the warning message issue, if the vehicle's electronics are powered up in a different sequence to normal.

From what I can gather, the Toad has two independent circuits which it breaks to achieve immobilisation. I am guessing that they are probably relay contacts, to guarantee isolation from the immobiliser electronics. What these are connected to is at the whim of the installer, and could have been chosen from one or more of Starter Solenoid, Fuel Pump etc. Quizzing the previous owner may tell you which it is.

Temporarily removing or bridging the immobiliser connections would prove whether it is "guilty" or not.

Interestingly, if I press the Toad first before inserting the key, no temp warning!

nigel garland said:

Interestingly, if I press the Toad first before inserting the key, no temp warning!

Click to expand...

I'm not familiar with Toad systems, but sounds like that is your answer.

When you energise the ignition, the vehicle carries out a number of self checks including all the warning lights and instruments in the cluster. It is always good practice to wait for the instrument lights to go out before starting the engine, and not doing so can be a cause of the generic failure warning light sporadically illuminating on the newer vans.

So it may be that with the Toad immobiliser on, first stage ignition is either not getting a signal it expects, or an erroneous signal, and unsetting the immobiliser before energising the ignition resolves that.

Thanks for all the input. Gratefully received.

Far too many complicated electronic bits in these modern vans. Didn't get any of this in my 30 year old 1.9 Ducato. Simple mechanical fuel injection. Was left for 6 months and started first turn of the key.
Mind you it was pretty sluggish, didn't like hills or corners or much above 50mph!

Is this a stored error code that hasn't been cleared?

Run MultiECUScan(MES) and read the ECU for errors.
Clear the old stored codes.

I don't have the 2008 2.3 JTD. (unsure of your setup)
In the 2006 2.8 JTD, I have a temperature sensor and a temperature sender. 2 separate sensors.
The Sender only does the temp guage.

The CTS or temperature sensor talks to the ECU. It is important.
MES can read the temperature CTS in realtime.
Perhaps it is faulty or the connector needs replugging?

I would put a diag tool on and read the CTS temp sensor in realtime.
This will tell you
1. the temp sensor works or not.
2. Show you if the temp sensor has an intermitant fault.
3. Tell you if the error code is just old and stored.
4. You should clear the code if it is old. It shouldn't return unless an issue.

Note. My thermostat failed. It tripped an overheat with the temp sensor and was real.

You do not want false alarms on this.

Hi Peter (IceVovo)

Not wanting to go off topic but...
You mentioned 2006 2.8 JTD, (Same as mine), and you mentioned MultiECUScan(MES)

If you have anything which reads codes on this vehicle, can I please have a make and model number, please

I have purchased a few, (el-cheapos), and borrowed a few more, probably el-cheapo, but am unable to find one which works, on my engine

I think it was the TOAD alarm/immob causing the message

I don't have any error codes recorded & no further warning messages since I have altered the start-up procedure by pressing toad fob first before inserting key

Thanks for all your efforts