c5 2.0 HDI FUEL PRESSURE SENSOR

JOHNR8195 · Post by **JOHNR8195** » 07 Mar 2010, 17:55

Hi, My c5 hdi is in limp mode and the engine light is on. The fault code is P1166 "fuel pressure sensor". I have been told that the sensors are not always the problem. Has anyone got any advice please, these sensors are £150 and might not actually cure the fault!

DickieG · Post by **DickieG** » 07 Mar 2010, 18:26

Check the connection between the loom and sensor, give it a clean and you may well sort it out, I did on a Picasso.

kaostheory · Post by **kaostheory** » 07 Mar 2010, 20:10

Whereabouts are you based i have 3 spares lying around that you could test before buying one if you are local? But you will find that the fuel pressure sensor fault can sometimes be completely wrong. The last time i had that fault it was actually the pressure regulator at fault. Expensive lesson at £108 for the new sensor.

Rhys

cachaciero · Post by **cachaciero** » 10 Mar 2010, 09:14

kaostheory wrote:Whereabouts are you based i have 3 spares lying around that you could test before buying one if you are local? But you will find that the fuel pressure sensor fault can sometimes be completely wrong. The last time i had that fault it was actually the pressure regulator at fault. Expensive lesson at £108 for the new sensor.

Rhys

Examination with a Lexia will tell you what it thinks the pressure is (from the sensor) then a X check with a pressure gage on the fuel line will enable an accurate diagnosis.

I would expect that a shot sensor would show up on the lexia as something other than 0 PSI with no pump running.

cachaciero

wheeler · Post by **wheeler** » 10 Mar 2010, 12:34

It would have to be an awfully big pressure gauge to use to check the rail pressure.
If i remember right if the pressure sensor or it's wiring go open circuit the pressure reading defaults to 450ish bar.

TopDonkey · Post by **TopDonkey** » 10 Mar 2010, 13:45

I've got a 1000 bar hydraulic pressure gauge and a 12" hydraulic connector that i use to verify high pressure pump output when cranking, it was only about £15 and £10 for the hydraulic line to be custom made, it was invaluable before i got lexia, and i still use it now to check how fast pumps can build pressure as you can determine how worn out they are with it, which lexia cant do

TopDonkey · Post by **TopDonkey** » 10 Mar 2010, 13:51

Also, most hdi's have got a modified 6" extra piece of loom fitted that can cause problems, so when you unplug the rail sensor connector, follow it down another 6" and you will likely find another plug and socket that you need to check, i have had to cut the extra connector out on my old car and solder it together because of a dodgey joint there