Auto Handbrake fault

[Aland97]

Good evening to you all..

Hopefully someone can shed some light on this as I’m sure I’m not the first to have this!!
Vehicle is:

C4 grand Picasso 57 plate 1.6 diesel auto

I’ll get straight to the point…
The hand brake will not release, the red (P) on dash flashes constantly and the warning “handbrake fault” is displayed briefly. At first someone said about the battery and because it was sat through winter I put a brand new battery on it and still had the issue.. I have cleaned every terminal and connection I can find and the battery voltage is a steady 12.2v followed by 14.4 with the engine running with no fluctuation up or down etc… I plugged it in and and got P0562 ecu undervoltage… have tried resetting/clearing but it remains and says “permanent fault” underneath. I’m now thinking go straight to checking the handbrake ecu/motor under the seat but apart from checking the condition of the connection I’m not sure there’s much more I can do, so before I start ripping things apart does anyone know of anything else I can check etc that may save me some time and hassle… thank you

[Lcs1010]

Hello I also have ESP/ASR And parking brake (auto) failure. No codes are coming through though
The parking brake does work if I do it manually but it no longer does it automatically. Limp mode is on as is the service light. Can anyone help please

[GiveMeABreak]

@Aland97

First it may help us if you post your VIN up so I can identify exactly what you have (please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff).

In the interim this is the explanation of the specific fault code you mentioned, but as you can see it's not necessarily the vehicle battery, but whether enough voltage is reaching the ECU. So I would be checking the ABS / ESP module connectors and don't just focus on the wiring, but check the actual pins in the connector blocks as these have been known to become loose or broken.

The ESP ECU is a key component and will impact on the ability of other systems to operate correctly too. It also controls the handbrake ECU, so all related wiring should be checked. At least you know the voltages that should be checked.

Id you want a wiring diagram for the ESP system for your specific vehicle, I can provide one once you have provided your VIN.

Fault Code:	P0562
Description of Fault:	ECU supply low voltage fault : Not characterised. The ECU supply voltage is monitored every 20 milliseconds The fault code appears in the following conditions: Possibility 1 The ECU is in regulation and the ECU voltage is lower than 9,2 V Possibility 2 The ECU is not in regulation and the ECU voltage is lower than 9,3 V Possibility 3 Voltage of the ECU lower than 8,2 V Possibility 4 Voltage of the ECU lower than 7,7 V Conditions of activation of the diagnostics: Vehicle speed higher than 6 km/h Ignition switched on
Conditions for Fault to clear:	Possibility 1 The ECU is in regulation and the ECU voltage is higher than 9,2 V Possibility 2 If the ECU is not in regulation and the ECU voltage is higher than 9,3 V Possibility 3 Voltage of the ECU higher than 8,2 V Possibility 4 Voltage of the ECU higher than 7,7 V
Downgrade Modes whilst Fault is active:	Possibility 1 Immediate cutting of all the speed control functions Electronic brakeforce distribution function inactive Switching of the electric parking brake to manual mode Possibility 2 Immediate cutting of all the speed control functions The electronic brakeforce distribution function is in down-grade mode Switching of the electric parking brake to manual mode
Switching on of the warning lamp and/or warning message	Possibility 1 ESP/ASR indicator lamp ABS indicator lamp Electric parking brake automatic functions deactivation warning lamp SERVICE indicator lamp Possibility 2 ESP/ASR indicator lamp ABS indicator lamp Electric parking brake automatic functions deactivation warning lamp SERVICE indicator lamp Warning lamp for handbrake, brake fluid level and brakeforce distribution malfunction Imperative stop warning lamp
Symptoms:	Lighting of the ABS and ESP warning lamps
Suspect Areas:	Electrical harness Incorrect battery voltage Fuses CONNECTORS; Screwed terminal

[GiveMeABreak]

Hello I also have ESP/ASR And parking brake (auto) failure. No codes are coming through though
The parking brake does work if I do it manually but it no longer does it automatically. Limp mode is on as is the service light. Can anyone help please

You will have a fault code, but if you are using a generic aftermarket fault reader then it will be unlikely to read some systems including the ESP. You'll need a professional level diagnostic tool to read these typos of ECUs, like a VCI with Lexia or Diagbox.

[Aland97]

@givemeabreak

That’s already some brilliant information thank you… my vin is as follows:
VF7**************[VIN obfuscated, can be read by forum staff]

Where is the abs/esp module located? Is it the part that’s under the passenger seat (mines a RHD).. so what your saying is that there’s a possibility that although the battery and alternator are showing fine: the voltage isn’t getting to where it needs to be to operating the handbrake.. I have been working on cars since I was 15 (now 42) and owned a car garage and done everything you can think of…….. but when it comes to auto electrics I just sit in the corner and cry haha so I appreciate all the advice and help I can get lol

[RichardW]

ABS unit and ECU is in the passenger wheel arch, in front of the wheel. Unit under the passenger seat is the handbrake motor.

Check the fuses on the top of the battery, and also the wires coming from them.

You really need to get it on Diagbox to see what is going on in live data.

[Aland97]

@richardw
Thank you, I have got a scanner (artdiag500) it states that it does live data so I’ll do that tomorrow but I don’t know what I’ll actually be looking for on it lol
All the fuses have been checked, and I’ve cleaned all the terminals on the fuses on top of battery and I’ve removed and cleaned the alternator connections too along with battery terminals and the ground that runs to the chassis etc

[GiveMeABreak]

@givemeabreak

That’s already some brilliant information thank you… my vin is as follows:
VF7**************[VIN obfuscated, can be read by forum staff]

Where is the abs/esp module located? Is it the part that’s under the passenger seat (mines a RHD).. so what your saying is that there’s a possibility that although the battery and alternator are showing fine: the voltage isn’t getting to where it needs to be to operating the handbrake.. I have been working on cars since I was 15 (now 42) and owned a car garage and done everything you can think of…….. but when it comes to auto electrics I just sit in the corner and cry haha so I appreciate all the advice and help I can get lol

That's correct. Stress and strain / vibration and servicing that involves unplugging and reconnecting the ECU plugs can all take a toll and are often the least looked at things. But a loose or broken pin can easily be checked for corrosion or damage. The fault code provided can't be specific in this case because it is not getting sufficient voltage or any voltage. But at least you have some pointers.

[Aland97]

Perfect thank you so far guys, I’ll update tomorrow with any findings etc and see what I can do!

[Aland97]

Right, I think I’ve done a data stream… I got some screen shots of it.. all the values you see are staying the same so done some screen shots as not sure how to upload the video…it says electric parking brake ecu supply voltage as 12v with just ignition on but now 14.4v with engine running so I’m confused why it still says undervoltage… does this make sense to anyone?

[Aland97]

Also should this be on 0%

[GiveMeABreak]

That's the bit I was looking as, as if your recall I said that the Handbrake ECU is controlled by the main ESP / ABS ECU.

General reasons why the EPB won't release:

• Vehicle configuration (multifunction screen)
• Downloading of the electronic parking brake ECU software
• Configuration of ECU ABS/ESP
• Parking brake cables
• Parking brake electric control
• Connectors
• Electrical harnesses

Of course for now you can release the EPB manually using the emergency release.

(7) Electric parking brake unlocking tool guide tube.
(8) Carpet cap.
The parking brake manual unlocking emergency mechanical control is placed under the front left seat.
The electric parking brake unlocking tool is a braided cable, stored with the tool kit.

To operate the emergency mechanical control, carry out the following operations:

• Move back the front left seat Maximum
• Remove the carpet cap (8)
• Pierce the electric parking brake (7) unlocking tool guide tube rubber sealing cover
• Engage the unlocking tool in the electric parking brake (7) unlocking tool guide tube
• Turn the unlocking tool clockwise until the parking brake is unlocked

[Aland97]

The tools not in the car unfortunately so I’ve got to get it off someone I know that has the same car… what’s the location of this esp/abs ecu? Is it in the engine bay or inside the vehicle?

[Aland97]

I’ve found the tool… but not sure about doing that just yet as I’m dying to find the actual fault… I’ve checked the plug and pins on the abs unit in front of the passenger wheel, it had a protective cover round it so guessing the original recall had been done… I’ve checked inside the car too on the handbrake motor and the small white unit that’s under the centre console etc… all pins and plugs look perfect… is there electrical components at the rear wheels that could need cleaning or checking? I can see some near the wheel but also directly in the middle near the rear beam but unsure what they are…

[Aland97]

Is this part the esp ecu?