Hi everyone. Hope somebody can help with our little problem, as the Volvo dealers are very unhelpful!!!
Our 2010 FH13-500 keeps throwing up a fault on the dash and occasionally goes into limp mode.
The fault is Engine Coolant Pressure Data Erratic.
The dealer I’ve spoken to has never had this fault before, so I’m hoping that someone out there has a bit more knowledge than they do!!
many thanks in advance
Neil
It’s not in the first flush of youth so has anything been done to it recently? It is either gaining pressure, losing it or there is an electrical issue. Is it showing any physical symptoms? Use of coolant, overflowing or leaking coolant, abnormal coolant temperature, decaying air pressure when engine turned off, or steam in the exhaust?
Is the ‘radiator cap’ on properly? Does the vehicle have a water cooled EGR system? Are there signs of oil in the coolant or vice versa? Standing alongside the vehicle can you hear any strange noises when the engine is running or immediately after shutting down?
Electrically it could be picking up a spurious signal from any one of numerous sources, have a short, a resistance, an insecure connector or simply a faulty sensor.
There are no pressurising issues with the vehicle. Over the last 12 months it has had a compressor, a turbo, a coolant sensor, a header tank and level sensor, a cooling fan, oil pressure switches with the revised wiring harness. When all the sensors/switches have been fit, the wiring has been checked and no faults found.
As its an intermittent fault, it is very annoying 
spike74:
There are no pressurising issues with the vehicle. Over the last 12 months it has had a compressor, a turbo, a coolant sensor, a header tank and level sensor, a cooling fan, oil pressure switches with the revised wiring harness. When all the sensors/switches have been fit, the wiring has been checked and no faults found.
As its an intermittent fault, it is very annoying
This is getting scary , I was always lead to believe anything Swedish was bombproof .
shugg:
spike74:
There are no pressurising issues with the vehicle. Over the last 12 months it has had a compressor, a turbo, a coolant sensor, a header tank and level sensor, a cooling fan, oil pressure switches with the revised wiring harness. When all the sensors/switches have been fit, the wiring has been checked and no faults found.
As its an intermittent fault, it is very annoyingThis is getting scary , I was always lead to believe anything Swedish was bombproof .
+1 an suprisingly impressive list of things done 
This hasn’t got something like the ■■■■■■■ demand-flow cooling system has it?
spike74:
Hi everyone. Hope somebody can help with our little problem, as the Volvo dealers are very unhelpful!!!
Our 2010 FH13-500 keeps throwing up a fault on the dash and occasionally goes into limp mode.
The fault is Engine Coolant Pressure Data Erratic.
The dealer I’ve spoken to has never had this fault before, so I’m hoping that someone out there has a bit more knowledge than they do!!
many thanks in advance
Neil
I’ve not personally come across this fault. I didn’t think they had a coolant pressure sensor, but if they have I would go for a sensor or a wiring fault to the sensor.
Many thanks for the replies guys!
I’ve spoken to Volvo, and this model doesn’t have a coolant pressure sensor, just a temp. sensor, and a level sensor in the header tank.
It’s sounding more and more like an electrical fault 
Volvos have a lot of wiring that isn’t used, it’s like they fit the same wiring loom to all FH’s but a lot of the wiring ends in blanking plugs if it isn’t required in a particular truck. Perhaps you’ve got a intermittent short in a cable that would be connected to a pressure sensor in another truck but isn’t required in your truck. How you would find it however is another problem.
Have you had a non genuine dash or Ecu fitted at any time that might be not be fully compatible to your truck?
shugg:
spike74:
There are no pressurising issues with the vehicle. Over the last 12 months it has had a compressor, a turbo, a coolant sensor, a header tank and level sensor, a cooling fan, oil pressure switches with the revised wiring harness. When all the sensors/switches have been fit, the wiring has been checked and no faults found.
As its an intermittent fault, it is very annoyingThis is getting scary , I was always lead to believe anything Swedish was bombproof .
The trouble is, very few of them are Swedish, those ones are bomb proof, the Belgian ones not so much and the US built models are made of cheese.
That’s a comprehensive list of new parts, the new compressor raised my eyebrows, but as it’s intermittent it’s highly unlikely to be a mechanical fault, especially an air leak from any of the usual suspects, leaks leak all the time and they get worse over time.
Electrical is my guess, either a sensor or a plug, sensors are witchcraft and sorcery, so I would check all the plugs on the coolant sensors and make sure all the pins are secure, slap some electrical grease on them and keep your fingers crossed.
Do you have any information about when this warning appears in relation to what the vehicle is doing at the time?
Since you have said this model doesn’t have a specific sensor for that purpose, you are going to need to know from Volvo how the ECU does in fact sense coolant pressure. In a closed system pressure will be a function of temperature so it would be possible to interpret a CTS signal for this purpose. With the two being interrelated then one would expect to see a temperature fluctuation as well, which would account for it going into limp mode.
Are Volvo saying that no Volvos are fitted with a coolant pressure sensor or just that yours isn’t? If other year models are so fitted then it may well be that it is picking up a spurious signal via redundant wiring fitted to your vehicle.
Erratic does indeed seem to indicate an electrical interference with the signal received by the ECU as the most likely cause. However if the signal is genuine then there must be a physical reason for this erratic behaviour. You have had one CTS renewed, but is there only one CTS fitted? Older vehicles commonly had a CTS for the temperature gauge and another for the ECU. Is there any possibility that the coolant had become contaminated in the past and a CTS probe has become coated in diesel or oil?
There are other possible though what would seem to be unrelated physical causes, unless the vehicle is genuinely overheating, as is the theoretical possibility of the ECU comparing data from other sensors and deciding one reading is implausible. This would be particularly relevant if the vehicle does in fact have a pressure sensor, something as simple as an ill fitting pressure cap would allow a high coolant temperature signal to be allied to a low coolant pressure signal and possibly a high oil temperature signal, resulting in a triggered code.
The questions are what led up to the coolant temp/level sensors,fan and header tank replacements and is the ‘revised’ wiring harness referred to compatible with the original ECU ?.
As for Swedish,Belgian or US Volvos the motors all seem to be based on--------a French design. 
Does it only do it when it’s wet?
My fh 13 has been de rating,volvo said it was a sensor for piston cooling temp.by the way I run mine with the header tank cap loose,so there’s no pressure in the system,and it wont blow any hoses off.it never gets hot or blows coolant out.