P2562

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careca
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P2562

Post by careca »

Hi experts, i read a couple of threads on this error, but did not come closer to the solution. Hdi 2.0 136hp.
I had something like this happen before, i replaced the valve that's in the "back" of the engine, that controls the vaccum to the turbo.
Car went fine for 3 months or so. Skipping to now, i lose turbo very quickly.
Connected lexia to check turbo pressure and there is a big difference between "required" and "achieved". Pic attached.
There is another valve, that's closer to the starter, under the diesel filter, seen someone say that one could be the culprit.
Opened the filter, and the sponge was totally broken, cleaned out, put a new one, no change, also the pipe was not blocked with any pieces of foam.
I did test the valve with a manual vaccum pump, and it leaks, isn't it supposed to hold the vaccum?
There's no change if i apply 12v, the other one i replaced also did this and leaked through the body, in the coil side of the valve..
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Last edited by myglaren on 30 Dec 2023, 19:09, edited 1 time in total.
Reason: Images rotated
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GiveMeABreak
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Re: P2562

Post by GiveMeABreak »

Fault Code: P2562
Description of Fault: Turbo position copy signal fault: Positive gap between the reference turbo position and the position measured. The fault is forwarded if the difference between the reference value is above 30% at the actual position (For at least 8 seconds).
Conditions of activation of the diagnostics:
  • Engine speed above 1500 rpm
  • Engine torque higher than 120Nm
Conditions for Fault to clear:
  • Driving for 5 minutes
Downgrade Modes whilst Fault is active:
  • Inhibition of the flowmeter plausibility faults
  • Torque limitation for traction control
  • Deactivation of forced regeneration of the particle filter by the diagnostic tool
Symptoms:
  • Lack of power
  • Noise
  • Smoke from the exhaust
Suspect Areas:
  • Turbocharger position copy sensor
  • Electrical harness
  • Connector
  • Vacuum problem
  • The variable geometry of the turbocharger is locked
  • Particle filter
  • Air metering valve
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Marc
careca
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Re: P2562

Post by careca »

Hi, thanks, that goes in line with what i had read. I ordered the valve that i think goes into the egr,(OE 9654282880) since i dont think it's supposed to leak this way and not hold vaccuum.
Need to check once it arrives, will then report back.
So far have not found any vaccuum leaks. Doubt it could be the position sensor, but who knows.
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careca
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Re: P2562

Post by careca »

Valve has arrived today and was fitted, before installing i compared the vaccuum holding ability of both, and the new one holds on better, but not at 100%, after it was fitted, there was no change, still no turbo.
More testing ensues.
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GiveMeABreak
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Re: P2562

Post by GiveMeABreak »

I would be checking the turbo hoses too - even the slightest leak from a crack or small hole can cause havoc.
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Marc
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Re: P2562

Post by careca »

Today i tried to troubleshoot this issue again, to no avail. One thing i just cannot understand is this behaviour: apply manual vaccuum to the turbo actuator, it moves. Attach a pressure gauge to the exit of the electric solenoid valve, plugged into the spot where the line from the turbo connects to check for vaccuum, there is plenty. Connect the line from the turbo as is supposed to be, turn on the motor, and give it throttle while visually checking for movement in the turbo actuator rod, there is none. I don't understand, why is it that there is vaccuum but the actuator only moves if i apply vacccum manually?
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GiveMeABreak
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Re: P2562

Post by GiveMeABreak »

Surely the turbo only kicks in when required and as it's electronically controlled this won't happen unless the engine ECU commands it - whereas you are manually forcing the unit to create vacuum...
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Marc
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Re: P2562

Post by careca »

"Surely the turbo only kicks in when required and as it's electronically controlled this won't happen unless the engine ECU commands it"

Thanks, yes, i believe it does open by ecu commands, as was the case when i forced it through the lexia actuator test, where it cycles the electric solenoid, and the turbo rod moved.

A new development, i did manual vaccum directly to the turbo unit/solenoid, whatever you want to call it, and gave it a couple of good throttle pumps, while looking at lexia,
still no boost, surely this way the turbo is forced to make at least some boost, correct? The current boost value basically doesn't change at all, 980 to 1020 or so mbarA.
Compared to the required, or setpoint, which varies a lot.

I am thinking about what is left, no vaccum losses, the position sensor does output aparently correct values, that are reflected on lexia,
so maybe a turbo main hose that i missed completely and no hissing noises, like you suggested or the turbo has failed internally...or something else i cant think of.

In an unrelated, (i think) note, there is a new code that reads "temporary fault engine torque regulation" in the abs ecu.
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Re: P2562

Post by GiveMeABreak »

For this engine Citroen use certain tools to check the turbo pressure which involves attaching a pressure take off extension, union, hose, sleeve & gauge. When all are attached correctly with the air hose removed the engine is revved to 4000 r.p.m. The pressure should be 1 ± 0,2 bar(s).

So I don't know if you can check this casually without the correct equipment, because the turbo only kicks in at a certain range, so the equipment is likely used to measure this accurately under these test conditions.
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careca
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Re: P2562

Post by careca »

Oh my god! i got boost again! Now it all makes sense! So i basically plugged the vaccum line that goes into the solenoid that is under the fuel filter, this controls a butterfly valve in the intake, above the starter.
I have watched a video where the person explains about the intake of this motor, but there was a difference, in his car, this butterfly valve serves to bypass the intercooler, there was another pipe that goes direcly from the turbo into the intake, but in my car, that pipe doesn't exist, so i started to think maybe there is an obstruction, maybe this butterfly valve is closed.
Then i remember that when i applied vaccuum to the electrical solenoid, it would not hold the vaccum at all, then it clicked, if it doesn't hold vaccuum, the butterfly valve is closing, it's closed at all times, because the solenoid if allowing vaccum to go through, so i plugged it and now the butterfly is forced open which is it's normal state, and i have boost as normal!
A few questions remain, like, can i keep this plugged? Does it harm the motor? What purpose does the butterly valve serves, if there is no bypass anyway? Is it a left-over from a slightly different version of the motor?
It doesnt make sense that they would leave this in without a purpose..
The youtube video:
The pictures show the valve i replaced, to make it clear, i bought a new one, going off of those numbers that the old one has.
One picture is from the youtube video, so you can clearly see the pipe there, whereas on miine there is none.
Attachments
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careca
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Re: P2562

Post by careca »

Hi there! unfortunately the car is at it again, with the same error, just needed a bit more driving to set it off i guess.
Going by what @GiveMeABreak posted about the error being set off by a 30% difference between the two, "turbo position copy" and "turbo position setting",
i did some more tests, i placed a vaccuum pump with gauge on a T connected in the vaccuum line that goes between the solenoid exit and the turbo, to check for how much vaccuum is going there, which is what it shows in the picture at idle. Around -0.3 bar.
The turbo solenoid is a new valve, has maybe 2 months, and it holds vaccuum very well on the bench while closed.
I'm at a lost as for what i can do next, it seems it's the ecu that is doing this and opens the valve too much,
cutting off the vaccuum that would increase the turbo position, ergo, pressure.

My question is this: Should the "turbo position copy" and "turbo position setting" values be similar at all times?
Or does it only matter above a certain rpm or demand?

The picture is at ok/idle, when in limp mode the "setting" value goes to zero and the copy goes to 10%.

Things i can exclude:
Turbo and "turbo position copy" sensor are OK, makes good pressure if i force vaccuum until the sensor shows 100% and give it some throttle.
Vaccuum leaks, there are no leaks.
Vaccuum pump bottoms out the vaccuum gauge.
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Last edited by myglaren on 15 Jan 2024, 19:26, edited 1 time in total.
Reason: Images fixed
toolfan
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Re: P2562

Post by toolfan »

I am dealing with the same issue on the same model. I did not find yet the solution. But what I noted, when all is fine, the turbo-pressure acutator should move to 100% when starting up the engine. Pulling that rod into the vacum actuator. You can feel it by hand, when somebody starts the engine. Also now on my car, I get only 0.2 bar vacuum at the outlet of the vacum solenoid. So only very little movement to actuate the turbo, means little pressure. Somehow the ECU seems not to send a signal to the solenoid, or the signal is wrong. Cracking my head what to do next.
careca
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Re: P2562

Post by careca »

Hi, i never noticed if the actuator moves to 100% in mine, does it reflect in lexia? I will take note of that. How long does it remain at 100% from start?
Got a plan, i will measure the volts at the plug for the solenoid, if i need less volts, maybe will apply a resistor or something like that. This would cause the valve to restrict the atmosphere port a bit more and allow more vaccuum pressure in the turbo, and thus, more pressure. Would be nice to have a "working" car and compare the voltages to it.
I assume the ecu sends variable voltage to the solenoid, could also be by pulses(?).
Seems like the end goal is nullifying the vaccuum, the more volts, the more it nulls the vaccuum, this is based on the observation that the resting position of the solenoid valve closes the circuit to the atmosphere part,
so 100% of the vaccuum goes from in to out, those 2 ports where the hoses connect.
toolfan
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Re: P2562

Post by toolfan »

Hi, one thing for sure, it is a pulsed signal to the solenoid. When everything is ok, it did on a multimeter jump around 6 volts. (Of course, better connect a oscilloscope). Now, without a correct working solenoid, it shows just the 14.2 or such volts on the connector of the solenoid. Something hinders the ECU to transmit the correct signal. But a good idea with the resistor, would at least give us some hints! Let us know!

What I couldn't check, is the movement of the turbo-actuator when driving - holding down my hand is already quite challenging (heat) in idle!

I even asked a ECU repair company if the ECU is damaged. They told me, this is very unlikely on this function.

I also checked the wires from the ECU to the solenoid, not found (yet) any damage.

I then further exchanged the maf sensor in the intake, as I was told this can deliver wrong signals without showing an error on Lexia. And in some cases, the intake temperature showed -49°C on Lexia, also a kind of error. So far, nothing changed.
careca
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Re: P2562

Post by careca »

Interesting.
I will do the same and report back, sadly don't have access to an oscilloscope, yet. I've seen multimeters with that function, not sure they're any good.

When you say you checked the wires from ecu, do you mean just visually?

One idea would be to remove the plug on the ecu, short the wires on either side, and do a resistance check on the open side.

I suspect this is kinda useless because what we seem to have, is a connection that is, at the very least, too good, if any wires had failed or the connection was more resistive, seems to me the solenoid would tend to close/return to it's resting state, applying full vaccuum. Or am i seeing this wrong? Or maybe with more resistance the pulses would simply be more frequent to reach a determined setpoint. Oh if i had a known good ecu I'd replace it, just to exclude that out.

Ps: I use a mirror to check the movement, no burning hands haha.