Engine Check Light - pre supply pressure sensor
 

On my ZT CDTi Auto, a few times recently the "check engine" message has flashed up.. only for a second or so, it's not stayed on.. but has never done this before. I connected it up to "TOAF" and that tells me the error code is "1255 pre-supply pressure sensor".

Just wondering if this is something i need to address urgently.. could the car break down due to this or is it something i don't need to worry about too much? I wasn't sure if i should fit a new sensor, or if it could be due to something else.

The car runs pretty well, though saying that it really doesn't like steep hills!.. really seems to struggle sometimes but i'm not sure if these cars are always like that as it's quite a heavy car and not a massively powerful engine? Or maybe there is something wrong with mine (it does have about 195k on it now, but i have had it serviced properly, injectors reconditioned etc..)

I'm afraid I have no real experience of the diesel engine, but could it be one of the fuel pumps wearing out, struggling with delivering the required fuel pressure? Hopefully someone will come along with some more help. :o

Pull of the electrical connector on the underbonnet diesel filter, make sure the pins are clean then replace it.

Quite a common thing on the diesels for causing the engine light.

Thanks for the replies, I will check/clean the plug on the sensor in the first instance then. The fuel pumps should be okay as they were both replaced recently.

Is it normal for the cdti auto to lack power going up steep hills though? Mine just doesn't want to pull, and there will be sometimes a violent jerk from the gearbox as it seems to try to change down then immediately back up again. It's ok to maintain speed going up these hills but it won't accelerate..

Struggling up hills in a diesel points in my mind to a fuel injector beginning to fail - i would do a leak back test to confirm or discount that as the cause.:shrug:

Struggling up hills in a diesel points in my mind to a fuel injector beginning to fail - i would do a leak back test to confirm or discount that as the cause.:shrug:

When was the fuel filter last changed? Might be worth putting a new one in.

The engine can go into limp mode with reduced fuel pressure on the low pressure side so I'd look at that first before considering anything on the high pressure side.
If the UBP has been replaced recently then check that the clear plastic inlet pipe cover, if fitted, was removed before fitting the pump, as that will cause exactly the same symptoms if it is wedged in the pipe under the UBP.
Came across this a couple of years ago after the owner had been advised by a BMW garage that he needed to replace the HP pump. :duh:

Thanks for replies - will check those points - although it shouldn't be the injectors - had them recond fairly recently - before that it was struggling to start but now starts very easily, just doesn't seem to have full power when putting my foot right down ..