[Warning Light] temperature warning light

[crossvale]

I'm getting the overheating warning light and "STOP" light flashing from start up. It's obviously not overheating and the lights go out after a mile or so. I have had overheating problems in the past but sorted now so I'd like to be sure the system is working as it should. 
Any suggestions for cause and cure.
Thanks
(Mine is 2003 Multispace 2l TDI)

[Sol]

When you say you sorted overheating problems, what did you do?

(Hopefully not RadWeld etc)

A bit of background might help us to follow the trail.

[geoff]

Can I assume the coolant level is correct ?

[crossvale]

When you say you sorted overheating problems, what did you do?

(Hopefully not RadWeld etc)

A bit of background might help us to follow the trail.

Had the head skimmed, new gasket etc, seemed to do the trick.??

[crossvale]

Can I assume the coolant level is correct ?

Coolant checked out ok.

[Sol]

Might just be a bad sensor or damaged wires from when the head was off. If you get a Bluetooth OBD reader and the torque pro app, you can pair it to the phone and read live data from the coolant sensor..that would confirm if it actually is going over 90 etc. Bluetooth OBD plug is about £20, I've got a vgate one (orange model) and it supports all PSA protocols. As does the Carista one (even though their app doesn't work on PSA cars) and I can read every sensor in the car live. It also reads and clears fault codes. Torque pro is about £2.50 off the app store.

[crossvale]

Might just be a bad sensor or damaged wires from when the head was off. If you get a Bluetooth OBD reader and the torque pro app, you can pair it to the phone and read live data from the coolant sensor..that would confirm if it actually is going over 90 etc. Bluetooth OBD plug is about £20, I've got a vgate one (orange model) and it supports all PSA protocols. As does the Carista one (even though their app doesn't work on PSA cars) and I can read every sensor in the car live. It also reads and clears fault codes. Torque pro is about £2.50 off the app store.

Thanks  Zion. My thoughts were that it is probably an electrical fault. The head rebuild was about a year ago and this problem has only just started. True, I haven't done a lot of miles due to lockdown but I'd imagine this would have shown up sooner. I'll see if I can locate the sensor and check the wiring for obvious faults. The bluetooth OBD looks like it could be a useful investment, I'll check it out.
Once again, many thanks.