"Cylinder head coolant valve" problem

[Johnny31]

Did a casual scan yesterday and OBDeleven came back with the following:
P199E00 - Cylinder head coolant valve Open circuit
Intermittent
Date: 2024-05-05 09:03:10
Mileage: 168216 km
Priority: 2
Malfunction frequency counter: 55
Unlearning counter: 255
Engine speed: 0.00 1/min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 19 °C
Intake air temperature: 14 °C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 10.980 V
Dynamic environmental data: 20962613BA00009DF714B30D2911390000133A0B0512FB0B14

The engine is 3.0TDI - CDUD.

Is it the valve itself that needs replacing or is there something else more sinister underneath? It cleared and not returned (as you can see, it happened in May and hasn't reoccurred).

Tnx!

[bluezie]

The coolant valve is vacuum operated, and the vacuum control valve is mounted on the top of the engine behind the oil filter. The most likely cause is a bad connection in the plug, or a broken wire in the loom, particularly where it enters the plug.
BTW, if you are loosing coolant with no obvious leaks, its very likely to be the coolant valve. Shine a good torch into the bottom of the Vee, and see if there is any coolant puddling, if so brace yourself, as it's a massive job to change it!

[Johnny31]

The coolant valve is vacuum operated, and the vacuum control valve is mounted on the top of the engine behind the oil filter. The most likely cause is a bad connection in the plug, or a broken wire in the loom, particularly where it enters the plug.
BTW, if you are loosing coolant with no obvious leaks, its very likely to be the coolant valve. Shine a good torch into the bottom of the Vee, and see if there is any coolant puddling, if so brace yourself, as it's a massive job to change it!
Hope not... Fingers crossed as never had issues with the coolant level and it all looks ok.