C5 X7 cutting out

[Agour]

Hi all!

My 2009 x7 randomly cut out yesterday.

After about 30 minutes of driving, the engine faded out over about 2 seconds, and then stopped.

I restarted the car, and it would cut out again after 20 seconds.

I plugged a computer in and got errors

[*]P0183 diesel fuel temperature signal. Short circuit to positive or open circuit or value too low
[*]P0181 diesel fuel temperature signal. Temperature change coherance.
[*]P1351 pre heating relay circuit.

I have a lexia on order, but it will be a few days away.

Fuel pressure seemed to be jumping around a lot at idle.
Reference would be 240, and it bounce around constantly between 220-260.
When applying revs, it seemed to get more stable.

Fuel temperature seemed normal - rose to about 30c after 10 minutes of idling.

I've ordered a new fuel temperature sensor.

Any ideas what else to check? From reading the forum - it seems like it might be the fuel pump pressure regulator?

VIN - VF7**************[VIN obfuscated, can be read by forum staff]

Thanks!

[mickthemaverick]

I'd fit the new sensor and then reset the codes and run it again before you start chasing rainbows!!

[Agour]

fair point!

Do you know where the sensors are located (both the fuel temp and fuel pressure regulator)? I had a quick look under the bonnet and couldn't see them..

[mickthemaverick]

I think a read through this thread will help you out:

viewtopic.php?p=497190#p497190

[PaulC5]

Before you delete the codes look at the freeze frame data and note it down. These are the values of sensors when the last fault was stored. They may give a clue as to what happened. This data is deleted when the codes are deleted hence why it should be noted first.

I do not know which engine you have but on our 2007 C5 2.2 hdi the fuel pressure regulator was attached to the bottom of the hp fuel pump. I was going to change it but access was too limited, needed long thin torx/allen bits (cannot remember which) but I swapped the car before doing anything. To see it I needed a mirror/torch and to see what part number it was I took a photo of its reflection in the mirror. PF Jones sell the parts as new and also at a lower cost reconditioned.

[Agour]

Before you delete the codes look at the freeze frame data and note it down. These are the values of sensors when the last fault was stored. They may give a clue as to what happened. This data is deleted when the codes are deleted hence why it should be noted first.

I do not know which engine you have but on our 2007 C5 2.2 hdi the fuel pressure regulator was attached to the bottom of the hp fuel pump. I was going to change it but access was too limited, needed long thin torx/allen bits (cannot remember which) but I swapped the car before doing anything. To see it I needed a mirror/torch and to see what part number it was I took a photo of its reflection in the mirror. PF Jones sell the parts as new and also at a lower cost reconditioned.

I'm in diagbox now and have found the fault codes, is this the freeze frame data you were talking about?

P0181 coolant at 54c and fuel at 48c seems a little wrong.. I would expect that coolant would be significantly higher than the fuel temp?

[Peter.N.]

The easiest way to get to the pump is to take the computer out - not as bad as it looks.

Peter