How I solved a P2564 on my 2011 Citroen C3 with the 1.4 HDi engine

[D4nical]

Hey everyone

I wanted to write this post so it could be of help when trying to solve a P2564 error like I just had to do, I know these errors are very common especially with PSA engines so hopefully I can give some insight on the issue and share my thought process. I apologize in advance if it's a long post.

This error appeared suddenly on my 2011 Citroen C3 with the 1.4 HDi engine (code 8HR). A check engine light appeared while driving and the car went into some sort of soft-limp mode. I could accelerate but basically not past 2k rpm and/or 90 km/h.

I went and checked the errors with my laptop on which I have the Autocom 2021.11 diagnostics software (many thanks to crouchinggerbil for providing the necessary software to generate the activation key needed to use it which you can find in this post) and the following errors appeared:

• P1445: The quantity of additive injected into particle filter has exceeded the maximum threshold. The particle filter must be changed. Permanent
• P2562: Turbo signal. Position too far from the reference value. Not enough turbocharging. Intermittent.
• P1497: (Same description as P2562)
• P2564: Turbocharger position. Short circuit to ground. Intermittent.

Now I ignored the P1445 since I had this error since before the CEL so I focused on the remaining three codes and the first thing I did was to delete the codes and start the car again.

After starting the car and letting it idle the light reappeared after a couple of seconds with just the P2564 error.

After a bit of research I've found out that the main culprits for these issues are the turbo position sensor on the turbo wastegate actuator and the vacuum solenoid that controls it.

The first thing that I did was watching the real time values for the turbo position sensor and got these graphs out of it.
Immagine 2025-02-20 211419.jpg

So you can see on top the reference value which is what the ecu expects to read from the sensor. On the bottom graph it's the actual value that is read by the sensor (sorry if there isn't a full graph I'm still getting the hang of it).
Now when I saw the squiggly line for the actual reading I thought that the issue was with the actuator vacuum solenoid controller and thought that there could be a vacuum leak in between the solenoid and the actuator or inside the solenoid itself (which I now can be a possibile issue) here is a picture of the sensor so you can get a better idea, it sits in front of the engine on the passenger side right above the alternator.
PXL_20250217_180333891.MV.jpg
So I checked with one of those cheap manual vacuum pumps that I got from Amazon if there were any vacuum leaks from the n.2 port but it held vacuum fine. I then checked if there was air passing between the n.2 port and n.3 which would indicate a cracked or ruptured diaphragm by blowing air in the n.3 port and that also was fine. I then used a multimeter to check the resistance values and if there was continuity between the two prongs of the connector. On the continuity test the multimeter beeped showing that there was continuity between the prongs and on the resistante test it read 15 Ohm and since the only reference online I found said that the normal range is 18-20 Ohm I thought that there was some sort of internal short in the solenoid. After changing it with a new one (Febi bilstein Part No. 98 018 876 80 paid 34€ for it) the error persisted so I put back my old one and looked at the other suspect, the wastegate actuator position sensor which is under the turbo (I know that when reading this post it seems like I should've gone directly with this one but I was very tunneled vision on the first sensor which shows how inexeperienced I am).
So I went with removing the wastegate actuator to take a closer look at the position sensor by doing this:

1. Removed the heatshield on the hot-side of the turbo, two 10mm nuts on the upper side under the valve rocker cover and a 10mm bolt between the DPF and the radiator
2. Removed the turbo intake hose, one T20 screw on the airbox, one 10mm bolt on the turbo housing and unclipping the PCV hose
3. Disconnected the sensor plug from under the turbo
4. Removed the vacuum line from the actuator and the 10mm bolt that holds it to the sensor
5. Removed the two 12mm bolts that hold the actuator to the turbo
6. Removed the clip on the wastegate valve BE CAREFUL NOT TO LOSE IT IT'S VERY SMALL
7. Remove the actuator by sneaking it from under the turbo from the drivers side of the car

After looking at it I saw that it was cracked at the connector which would justify the intermittent short to ground, after changing that sensor for a new one (FISPA Part No.9671801980 paid 55€ for it) and deleting the codes the car ran just fine and the issue was solved.
Immagine 2025-02-20 221325.jpg

Here is another graph from today when I changed the position sensor.

Immagine 2025-02-20 211502.jpg
The top graph shows the new sensor readings (the small spike is me revving up to 1.5k rpm) which is nice and linear with the position reference value
The bottom graph shows the old sensor. The drop in signal I suspect was the short to ground that happened whenever I accelerated. I think that whenever there was a rise in rpm the vibrations from the engine shorted the sensor and once it leveled out the signal came back. I cannot explain why it is wavy tought, I thought that the wavyness in the signal was the culprit caused by a bad vacuum solenoid but with the new position sensor and the old vacuum solenoid I managed to resolve the issues.

I wanted to make this post since I couldn't find for the life of me some reference values for these sensors so I could know for sure which one was out of bounds. Hopefully with this post people can compare their readings to mine and solve this common issue with the PSA engines.

Thanks for reading.

[Viking74]

Nice description!
I recently bought a used Citroën C3 Diesel with the same specs as your car, engine light started to glow the second day after purchase.
When turning the ignition on, there was one sound alarm and a steady engine warning light turned on. The stereo display in the middle showed "Engine Fault".
Never tried to drive the car in higher speed with the car light on, cannot tell if the car went into limp mode.

Needless to say, I was worried I had bought a junk car.
The next day, this warning was gone when turning the ignition key. Workshop diagnostics showed error code P2564.
The error code has not been seen after this, but I am still a bit cautious.

It feels kind of sad that you need a computer and specialized software (which might not be free) to diagnose or repair modern cars.
I would assume the (legal) software comes with a price suitable for car repair shops, not for ordinary car users having less than 4 cars.
In case that error light reappears within the 2 months sales warranty I have, I will happily share the solution here.

[Rafik69]

Hello,help me,please Radio Code DELPHI F199BT

HW VER:28500895

SW VER:R12

TYPE NUMBER:FJ5 RBT M14

BT VER:ALPS UGZZFX202A

FGA P/N:0520395450

SUPPLIER:C150

S/N:00205

PROD DATE:2615

ODM NUMBER:1201 IMG_20250308_113415767.jpg