C5 X7 intermittent power steering loss

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Fin50
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C5 X7 intermittent power steering loss

Post by Fin50 »

Dear all

The situation:

- Citroen C5 (X7) 2010 1,6HDI, steel springs, VIN VF7**************[VIN obfuscated, can be read by forum staff]
- During cold start the power steering always starts and works like charm (light steering in low speed, less assistance in higher speed, no abnormal noises, no lack of assistance when turning wheel fast, etc)
- after driving some 5..10 minutes or more, if I stop the car and start it again (for example for refueling), power steering pump almost always fails to start. I get ”Ping-Ping”-alarm, and a text ”power steering faulty”.
- after driving few kilometers without steering assistance, the power steering seems to try to restart itself. Most often this attempt fails. After random 15...100kms pump eventually starts, and works until next stop and restart.
- I have never lost power steering during driving. The problem seems to be some kind of ”start-up self-diagnostics” of the pump?
- If the problem was intermittent communication loss between main ecu and GEP-ecu (power steering), it would trigger the "power steering faulty"-alarm also during driving, and set steering pump to a backup-mode (without speed sensitivity etc)?
- as one might expect, steering rack leaks. It is possible, that pump has been running dry, without fluide, before I bought the car.

Below you can see screenshots from Lexia. First three are taken when pump is working.
The last one ("Communication error") is when motor is running and pump is NOT working.

What should I do?
Connect lamps to permanent +12v and ”ignition-12v” pins, and check if there really is an intermittent loss of voltage?
According to Lexia, the pump is able to easily take more than 50Amps of current (without smoke..) when I turn the wheel quicly, so I do not expect bad contact in permanent +12v and earth connections.
I have removed connectors (2 thick wires + 3 thin wires) from pump. No visible rust/oxide there. I still cleaned the contacts and applied some grease on them. No effect.

Yours,
Fin
GEP_working_1.PNG
GEP_working_2.PNG
GEP_working_3.PNG
GEP_power_steering_faulty.PNG

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GiveMeABreak
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Re: C5 X7 intermittent power steering loss

Post by GiveMeABreak »

Your problem is likely to be with the Fuses, Electrical harness, Engine fuse box or the actual Power steering electropump assembly.

Fault C1209: The ignition+ supply of the electropump has not been detected - so the positive supply is intermittent and when it is, you loose power assistance.

Fault C1211: Vehicle high speed wake-up fault: Not characterised. The likely suspect here is the Power steering electropump assembly.

So that is the common suspect between the 2 faults.

There are electronics inside the power steering pump including the ECU 2 electronic cards. If you've checked the supply to the electropump several times and all looks fine, then the problem is likely to be internal. It can't really be a fuse as that generally will be a Maxi Fuse (MF3) and that also provides power for the radiator cooling fan so if you switch on your Air Conditioning and the fan starts up you know it's not the fuse.

Fin50
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Re: C5 X7 intermittent power steering loss

Post by Fin50 »

Thanks for help Marc.

Yesterday the power steering ecu brain-died completely. No more working pump even on cold start. No communication with GEP at all on Diagbox.
Before replacing the expensive pump, I would like to once more check the voltage supply to the pump.

Does anyone know which one (if actually any) of the three thin cables is "ignition+", or a "+12v wake up"-signal for GEP?
The two more thin cables are for CAN-communication? I guess I cannot do anything to check the CAN wires, but is it OK to put some load to "ignition+" wire to see, that there is good connection all the way? Any idea how much is OK? 10W lamp = about 1A? Or only high resistance multimeter?

Yours,
Fin

Fin50
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Re: C5 X7 intermittent power steering loss

Post by Fin50 »

Actually, the wiring diagram from battery to power steering pump would help a lot. There I will see which cable is the "wake up"-signal, and which fuse and relay are between battery and the pump in this cable.
Any idea where to get the diagram?

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Re: C5 X7 intermittent power steering loss

Post by GiveMeABreak »

Hi Pekka

Make sure you check fuse F7 in the engine fuse box as that is for the power steering.

7122 is the Power steering electropump and ECU.

Image

On the 5 pin Black connector: (Power Steering ECU)

Pin (3) is C712A Power
Pin (2) 9001C: Low Intersystem / Can bus
Pin (1) 9000C: High Intersystem / Can bus

2 Pin Black Connector (Electro Pump)

Pin (2) M712A: Earth
Pin (1) BB05: Power from Maxi Fuse 3

As for testing - I know that another member (EDC5) tried an older Peugeot electric power steering module for use on a non PSA vehicle - but the earlier pumps had a lot more pins (non-CAN) and 2 of these connections needed connecting up to live (in addition to the 2 pin supply of course) to get it to work. With the CAN system on your X7, I'm not sure if it will work without the control of the ECU via the CAN.

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Re: C5 X7 intermittent power steering loss

Post by wheeler »

I highly doubt it would work (correctly) as there would be no way for it to know road speed & steering angle for starters, at best it would likely run in downgraded mode & only give limited assistance.
As for the CAN lines, if you have access to a scope you could scope them to check for activity & that both signals are a mirror image of each other.

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Re: C5 X7 intermittent power steering loss

Post by Fin50 »

Thank you gentlemen. I appreciate your help!

Wiring diagram confirms the wire C712A is a +12v supply via relay. I will attach a lamp to this wire close to the pump, to see if I lack this voltage when the pump does not start.
Comment from Wheeler helps me slowly gain some understanding of CAN-signals. Unfortunately I don't have an oscilloscope. One day I will...

The symptoms (being: I have never lost power steering when engine is running, it has always happened during startup of engine), and the presence of fault C1209 "Ignition positive supply fault" make me think, that:
- Once the motor is already running, losing the ignition positive voltage (from wire C712A) does NOT shut down the GEP ecu (signals from CAN-wires keep it "alive"). It must be for safety reasons: sudden and unexpected loss of power steering during driving would be a disaster without a doubt!
- Instead of loss of steering assistance, loss of +12v during driving triggers fault C1209
- If there is no +12v present in wire C712A during startup, GEP does not wake up at all, and main ecu (what was his name..BIS or something) triggers fault alarm ("power steering faulty", ping ping)
(If someone reads this later, please notice these are NOT facts, just my speculation)

If I do get reliable +12 in the pin 3 at the pump, and pump still does not wake up, then I will consider contacting someone with a scope, or more likely drive to local Citroen-dealer and pay my pinky toe for new pump.

yours,
Fin50

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Re: C5 X7 intermittent power steering loss

Post by Fin50 »

Oh dear :o .

I was not able to read the numbers written in three thin wires, but there is two of them twisted to each other (white and green), and one separate brown wire. The brown wire went in the pin #3 of the connector, and gave steady 12,5V when ignition was on (14V with engine running). So I decided this is my "C712A" and connected 12V/5W bulb to this wire. The lamp glows bright when ignition is on. Power steering is still faulty (despite the presence of "ignition +12V"). It still may be bad connector, but I'm afraid it looks like a time for a new pump.

Now the interesting thing is: I also unplugged the 5A fuse F7 behind small "stuff locker" (sorry for my English..) next to steering wheel. Lamp still kept glowing - without fuse?!? Sure the lamp went off, when I turned of the ignition.
--> Is there another fuse with same number somewhere else :?:
If not, it makes me wonder if someone has done some kind of by-pass, that is feeding 12v to the pump from some other source. At least I have not noticed anything like that.

EDIT: All right.. Marc said above "check fuse F7 in the engine fuse box". So there are several "F7":s. Must check that tomorrow.

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Re: C5 X7 intermittent power steering loss

Post by GiveMeABreak »

Yes the engine fuse box (F7) is behind the battery in the engine bay - not the the fuses surrounding the BSI by the driver's cubby hole in the car on a left hand drive.

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Re: C5 X7 intermittent power steering loss

Post by Fin50 »

About part number for steering pump:
From repair manual I got the following information:
From RPO 12292 on the pump part number would be 4008 E3. (My RPO is 12379)

All right.. If I buy a second hand pump, do you Gurus think it is compulsory (or highly advisable) to get a pump from similar RPO-range (12292 or higher)?
There seems to be a couple of second hand pumps available from for example 2009 cars, with lower RPO.

-fin

(I don't actually know what is the meaning of text/number 0610 03 4400 30E in the top of the same page of manual. Possible a number of this page/"bill of material" for the components related to power steering pump? It is not a part number, right?)

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Re: C5 X7 intermittent power steering loss

Post by GiveMeABreak »

There are far more pump part numbers that than that Pekka, depending on engine and build date and very important to stick to the correct ones for your engine and year, as these will vary in their parameters.

4008E3 is the correct part number for a brand new unit for your DV6C. (£920.20) Plus surcharge.
There is also an exchange pump part number: 1673624780. (£946.56)

Prices are from Citroen today and include UK 20% VAT to give you an idea.

But do keep to the same part numbers - as these are designed to work with specific engine types / years. The 2 I have posted are correct for you C5 from your VIN.

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Re: C5 X7 intermittent power steering loss

Post by Fin50 »

Oh SH1T ! (chemical formula of the stuff they use, when they make car components which do not last even 1 million kilometer).

I will try to find a second hand pump.
Should I expect the BSI will start nagging me (in other words: "Faulty steering" or something like that) if I put there a GEP with wrong parameters?
Or..
Should I expect bad driving behavior, for example too much of an assistance in highway speeds or something like that?

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Re: C5 X7 intermittent power steering loss

Post by GiveMeABreak »

There are specific calibration files used for the differing engines / models and the like, and in addition the size of the wheels are also important amongst other things. So the specific units are calibrated for the specific vehicles they are fitted to. The power steering ECU talks to the other systems like the ESP ECU that also takes info form the steering wheel angle sensor etc...

So if you can stick to the same part number as it will be pre-calibrated and programmed for your vehicle. You probably won't be able to change anything in the software as it is a specific file that is downloaded and applied via the PSA servers.

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Re: C5 X7 intermittent power steering loss

Post by Fin50 »

Thanks for advice. I, however, went and bought a pump from 2009 model diesel C5. I got it so cheap that I was ready to take the risk it won't work. I also had just few days left before MOT-test.

The connector for two heavy wires (earth/ground and permanent +12V) was different type compared to 2010 pump. I soldered a temporary adapter using two 8mm female Abico-connectors, two flat pieces of copper plate (for male-connectors), and a few centimeters of thick 6mm2 cable.

"New" pump works totally fine. At least I have not notice any difference. I am aware, that I have not yet driven the car in slippery conditions so that ESP decides to take control. That will be the acid test for the pump compatibility. There will be snow in Finland quite soon..

Seller of the replacement pump will send me the right connector with few centimeters of wire. I'm about to replace original connector with that one. I have a "logbook" for the car, and I will write there what I did. That will help if someone else needs to work with GEP later. I'm also aware of the size of maxi-fuse --> I will keep that in mind when soldering the wires.

I also keep looking for right part number pump.

(Oh.. what was wrong whit old pump? Well, it had leaked some water in! The "electronics box" had a lot of aluminum oxide inside.)

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Re: C5 X7 intermittent power steering loss

Post by Dorcel »

Hi guys , i hawe similiar problem with my c5 20hdi 140hp 2011. Its go up or down randomly, parked or when i drive. Its just go up on highest lvl or down. I check lsd tank and its emty...now can u tell me how to refil ... its just like any other fluid or what