FIXED - C2 ABS ESC Speedo problem (U0122, P0501)

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amallaburn
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FIXED - C2 ABS ESC Speedo problem (U0122, P0501)

Post by amallaburn »

Helping a friend with problem on his car,...his ABS light and ESP light keeps randomly popping up.

Have checked OBD:

Getting U0122 and P0501
Shown in attachments

Have checked all fuses and all ok.

There has been a mud guard missing on N/S (passenger side, RHD) since he got it and that's where the ABS module is located, I managed to get the black cover off top of cables and it's quite wet and muddy but can figure out how to get harness out.

Did not have a jack to hand so couldn't remove wheel for a better look, but I'm planning on checking the connections on the harness and looking for ideas, instructions on how to get to the ABS module harness

Edit: The yellow clip that connects to where arrow is in picture was broken off by a mechanic who recently fitted new steering rack
Attachments
Broken Clip
Broken Clip
Screenshot_20210204-162242.png
IMG_20210204_131022.jpg
IMG_20210204_145214.jpg
IMG_20210204_143948.jpg
IMG_20210204_145220.jpg
Last edited by amallaburn on 14 Feb 2021, 15:02, edited 2 times in total.

ozvtr
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Re: C2 ABS ESC SPEEDO problem

Post by ozvtr »

amallaburn wrote:
04 Feb 2021, 17:23

Edit: The yellow clip that connects to where arrow is in picture was broken off by a mechanic who recently fitted new steering rack
That was nice of him. Neat trick seeing the ABS hydraulic block is nowhere near the the steering rack.

Have you managed to get the connector off yet?

Have you tried to get a screw driver (or pointed object) onto the yellow retainer and push it side ways (down, in the thumbnail). Both sides. Tried grabbing the yellow tabs at the end of the connector and pulling them outwards?

amallaburn
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Re: C2 ABS ESC SPEEDO problem

Post by amallaburn »

Will probably get it with a jack, didn't have one to hand but saw on a Youtube video that the connector comes off (

Could you explain via an image, that would be great

Just need a diagram for the pinout of this connector as struggling to find online

ozvtr
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Re: C2 ABS ESC SPEEDO problem

Post by ozvtr »

This video is no good to you (as far as the connector is concerned) because he has already undone the electrical connector.

If you go to the 7:00 minute mark you will see the two yellow tags (that I talked about) and you will note that they are "sticking out". Have a look at yours, they will be recessed into the body of the connector.

You will need to get a screw driver or long nose pliers onto them and pull them outwards, bit by bit, one then the other, as you pull the connector away from the receptacle.

The Lever (that is missing) has a cog-like shape that engages into those teeth on the top of those yellow locking tabs. Causing them to slide backwards and forwards in the connector as you move the lever.
retainingmech.jpg

amallaburn
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Re: C2 ABS ESC SPEEDO problem

Post by amallaburn »

Thank you, do you have any idea where I can find the wiring diagram related to this harness/connector?

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GiveMeABreak
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Re: C2 ABS ESC SPEEDO problem

Post by GiveMeABreak »

@ amallaburn If you pop your VIN up here (auto masked on submission) Ishould be able to get a diagram up for you. Is it the ABS system you need?

amallaburn
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Re: C2 ABS ESC SPEEDO problem

Post by amallaburn »

GiveMeABreak wrote:
08 Feb 2021, 15:38
@ amallaburn If you pop your VIN up here (auto masked on submission) Ishould be able to get a diagram up for you. Is it the ABS system you need?
Sorry it took a while, it's my friends C2 took a while for him to find VIN

VF7**************[VIN obfuscated, can be read by forum staff]

Have purchased one of those Diagbox cables with 7.83 on so will see if that gives me more details when I try run test.

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GiveMeABreak
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Re: C2 ABS ESC SPEEDO problem

Post by GiveMeABreak »

Ok, so that connector looks pretty exposed to the elements, so would not be surprised if water has gotten in.

Anyway here is the Electrical Diagram for the ESP system on your C2: The ESP Connector has a 47 Pin connection and shown below are the pins on all 4 sides just to make it easier to read - but these are all in the one connector block.

Image

Some Component Codes to Help You
7800: ESP ECU
7804: ESP accelerometer gyroscope
7000: front left-hand anti-lock brake sensor
7010: rear left-hand anti-lock brake sensor
7015: rear right-hand anti-lock brake sensor
7005: front right-hand anti-lock brake sensor

Here is the same information, but shows the wiring colour codes for the block (7800). Focus on the pin numbers and not so much the colours of the wires as PSA are known to change colours.

Image

If you need more help with the wiring colour abbreviations or some of the hardware component codes, have a look on the Wiki here:

https://frenchcarforum.co.uk/wiki/Elect ... ring_Codes

amallaburn
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Re: C2 ABS ESC SPEEDO problem

Post by amallaburn »

Thank you very much, I have searched for ages to find this.

I'll let you know how I get on.

amallaburn
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Re: C2 ABS ESC SPEEDO problem

Post by amallaburn »

I had a look through diagrams and the link to the code explanation

I've knocked the table below up in Excel for the 7800

Until my Diagbox arrives (and hopefully it is one of the clones that actually works) I am just armed with a multimeter and a standard OBD reader through Torque Pro and OBD Auto Doctor

Also need to know If I'm to ignore wire colours and focus on pin numbers, how are the pins laid out on the actual connector, will I see any numbers?

This is my thought process so far, please correct me if I'm wrong

Check voltage on connections between PSF 1 and 7800 ESP, (PINS 1, 8 and 32)
Check resistance between Battery Negative and 7800 ESP (PINS 16 and 47)
Check resistance across wheel sensors and compare 7800 ESP PINS (33 & 34) vs. (36 & 37) vs. (42 & 43) vs. (45 & 46)

Since the two DTC codes I read were U0122 and P0501 would that be a CAN BUS fault?
I have no experience with CAN bus but understand this
IDLEDATA
CAN HIGH2.5v3.75v
CAN LOW2.5v1.25v
Potential Difference0v2.5v
So I could check those wires , would they be 12 & 14 13* that head to Steering?

And I guess since P0501 DTC is to do with VSS and I believe I've read that the C2 gets it's VSS data from the ESP would this be from the Gyro or Wheel Sensors?



Also managed to get another one of those yellow levers for connector so when I next get to my mates car I should be able to get the connector off, the mechanic just took the lever off, I opened the black cover when I had a look at ABS when my friend told me about the missing mud guard, it did look dirty in there though, clicked cover back on after

This is what I've put together from the diagrams and links you sent
PINNAMECOLOUR CODECOLOURCONNECTS TOConnectors
1BMF3RGRedPSF1 (PIN 3)8 Way (NR-BLACK) Pin-3
8CM9FOROrangePSF1 (PIN 19) & ACCELERATOR / CRUISE CONTROL SHUNT? (2120)28 Way (MR-BROWN) Pin-19
119010KVEGreenINJECTOR (12--) Intersystem 2 Can Bus HIGH?.
129000QBGBeigeSTEERING & BSI (PIN 2) ?? Intersystem Can Bus HIGH?BSI 40 Way (NR-BLACK) Pin-2
139001QMRBrownSTEERING & BSI (PIN 4) ?? Intersystem Can Bus LOW?BSI 40 Way (NR-BLACK) Pin-4
149011KVIPurpleINJECTOR (12--) Intersystem 2 Can Bus LOW?.
16M780CVJGreen/YellowEARTH (MC10).
189010VEGreenESP ACCELEROMETER GYRO (PIN 2)ESP 7804 6 Way (GR-GREY) Pin-2
199011JNYellowESP ACCELEROMETER GYRO (PIN 1)ESP 7804 6 Way (GR-GREY) Pin-1
227831VIPurpleESP ACCELEROMETER GYRO (PIN 3)ESP 7804 6 Way (GR-GREY) Pin-3
297832RGRedESP ACCELEROMETER GYRO (PIN 5)ESP 7804 6 Way (GR-GREY) Pin-5
32BMF2BEBluePSF1 (PIN 2)8 Way (NR-BLACK) Pin-2
337011ARGRedFRONT RIGHT WHEEL SENSOR2 Way (BE-BLUE) Pin-2
347012ABAWhiteFRONT RIGHT WHEEL SENSOR2 Way (BE-BLUE) Pin-1
367022ABAWhiteREAR LEFT WHEEL SENSOR2 Way (BE-BLUE) Pin-1
377021AJNYellowREAR LEFT WHEEL SENSOR 2 Way (BE-BLUE) Pin-2
41442BRGRedHANDBRAKE2 Way (MR-BROWN) Pin-2
427031AVIPurpleREAR RIGHT WHEEL SENSOR2 Way (BE-BLUE) Pin-2
437032ABAWhiteREAR RIGHT WHEEL SENSOR2 Way (BE-BLUE) Pin-1
457002AJNYellowFRONT LEFT WHEEL SENSOR2 Way (BE-BLUE) Pin-2
467001ARGRedFRONT LEFT WHEEL SENSOR2 Way (BE-BLUE) Pin-1
47M780BVJGreen/YellowEARTH (MC12).
Last edited by amallaburn on 11 Feb 2021, 00:14, edited 2 times in total.

ozvtr
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Re: C2 ABS ESC SPEEDO problem

Post by ozvtr »

amallaburn wrote:
09 Feb 2021, 20:34

Check voltage on connections between PSF 1 and 7800 ESP, (PINS 1, 8 and 32)
Check resistance between Battery Negative and 7800 ESP (PINS 16 and 47)
Check resistance across wheel sensors and compare 7800 ESP PINS (33 & 34) vs. (36 & 37) vs. (42 & 43) vs. (45 & 46)
Yep good start
amallaburn wrote:
09 Feb 2021, 20:34
Since the two DTC codes I read were U0122 and P0501 would that be a CAN BUS fault?

So I could check those wires , would they be 12 & 14 that head to Steering?
You mean 12&13...but I wouldn't bother. Look where the engine ECU CAN BUS is coming from and going to. THROUGH the ESP ECU. If the CAN BUS wasn't working you would loose engine data. You haven't mentioned the loss of engine functions.
I do not know if the CAN BUS through-put is active or passive. If it's active, the loss of the ESP ECU would cause the loss of the engine and I don't see that as a sound engineering practice. Meaning; the whole ESP ECU could go out but the engine still works, if the connection is passive I.E. no electronics.
On the surface, it looks like the ESP ECU is dead or at least doesn't want to talk to any one. :lol: I would look more closely at the power connections you mentioned above.
amallaburn wrote:
09 Feb 2021, 20:34
And I guess since P0501 DTC is to do with VSS and I believe I've read that the C2 gets it's VSS data from the ESP would this be from the Gyro or Wheel Sensors?
Your C2 has a virtual Vehicle Speed Sensor. The speed is generated by the ESP ECU and put on the CAN BUS for any ECU that wants to see it. Lots of ECUs use the speed information, the dash, the engine ECU, even the stock radio uses the speed information to determine the volume in auto mode!!! Some versions of the C2 have an actual VSS on top of the differential at the back of the gearbox.
In your case the speed information is derived from the wheel sensors. I do not know if the speed data is derived from one...or more than one sensor.
The gyro is used to calculate the yaw-rate (spin) of the vehicle and accelerometers determine the direction of travel of the car, that in turn is compared to the steering angle. If they don't match, the ESP ECU interprets this as a skid and will "intervene".

amallaburn
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Re: C2 ABS ESC SPEEDO problem (U0122, P0501)

Post by amallaburn »

Thank you for your reply

Yes I meant 12 & 13

Engine seems to be ok I believe
Two other things he's told me I don't know if related to above problems.
Ignore if not related as I'd like to keep this thread to the original problem for the benefit of others reading

Throttle is sticking sometimes

When turning steering while stationary the faults come up dash
Attachments
Faults
Faults

ozvtr
Posts: 32
Joined: 13 Oct 2020, 01:11
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Re: C2 ABS ESC SPEEDO problem (U0122, P0501)

Post by ozvtr »

amallaburn wrote:
10 Feb 2021, 17:39
Throttle is sticking sometimes
Is the peddle sticking? Does the engine light come on?

If the engine light doesn't come on, then the engine thinks the peddle position and the throttle butterfly are are in alignment. Again you didn't mention any engine errors so I cant explain that one. Could it be a different type of fault? Can you describe the symptoms? If the throttle butterfly and accelerator peddle are not in alignment the engine ECU WILL throw a wobbly!
amallaburn wrote:
10 Feb 2021, 17:39
When turning steering while stationary the faults come up dash
Sounds like classic battery/charging circuit problems.
I've got a blurb over on the Citroen C3 owners with a step-by-step on checking the charge circuit. It's very difficult to test a battery but easy to test the charging circuit. If it's not the charging circuit then it's probably the battery.
https://citroenc3owners.com/tips-for-an ... t4313.html

amallaburn
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Joined: 04 Feb 2021, 17:01
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Re: C2 ABS ESC SPEEDO problem (U0122, P0501)

Post by amallaburn »

ozvtr wrote:
10 Feb 2021, 23:03
Is the peddle sticking? Does the engine light come on?

If the engine light doesn't come on, then the engine thinks the peddle position and the throttle butterfly are are in alignment. Again you didn't mention any engine errors so I cant explain that one. Could it be a different type of fault? Can you describe the symptoms? If the throttle butterfly and accelerator peddle are not in alignment the engine ECU WILL throw a wobbly!
Apparently when the faults come up the throttle sticks
ozvtr wrote:
10 Feb 2021, 23:03
Sounds like classic battery/charging circuit problems.
I've got a blurb over on the Citroen C3 owners with a step-by-step on checking the charge circuit. It's very difficult to test a battery but easy to test the charging circuit. If it's not the charging circuit then it's probably the battery.
https://citroenc3owners.com/tips-for-an ... t4313.html
Been told all the lights come up, engine and handbrake included

I will go and check charging circuit today and report back, I found your guide the link didn't work for me for some reason

ozvtr
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Re: C2 ABS ESC SPEEDO problem (U0122, P0501)

Post by ozvtr »

When the fault lights come up on the dash the throttle 'sticks'? Does it fail to respond (freezes) or returns to idle?

Hmm, yep, doesn't work for me either? I'll talk to the admin guys and see if there is a problem.