BSM B3 teardown - what is inside the BSM module

Citroen C3 BSM removal guide
Citroen C3 BSM removal guide
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My Name: Arfur Dent

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Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
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Engine name: DV4 16-valve diesel (90 PS)
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The C3 BSM module is the engine bay fuse box and this sits next to the battery and covers the hidden maxi fusebox.

If you want to remove the BSM module then follow these BSM removal instructions

Citroen C3 BSM B3 tear down to look inside
Citroen C3 BSM B3 tear down to look inside

With the BSM removed the fuses can be easily removed with a pair of needle nosed pliers and the fuse legs should be inspected for corrosion.

Corrosion on fuse
Corrosion on fuse

Inside the BSM is a circuit board with relays

Relays inside the Citroen C3 BSM module
Relays inside the Citroen C3 BSM module

The underside of the BSM is coated with a clear varnish and contains no components

Citroen C3 BSM B3 circuit board
Citroen C3 BSM B3 circuit board

and there is a computer daughterboard that takes CAN/VAN signals from the BSI and Engine ECU for the relays to act on.

BSM logic board
BSM logic board

These BSM units are still quite common, you can pick up a replacement here, on eBay, quite cheaply here.

But if they get rare or expensive then the relays are probably going to be of the most interest for replacement

51ND10-W1
51ND10-W1
Get the 51ND10-W1 here


512ND10-W1
512ND10-W1
Get the 512ND10-W1


V230676-A3001-D142
V230676-A3001-D142
and you can get the V230676-A3001-D142 here
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User avatar
My Name: Arfur Dent

Guru
Posts: 3423
Joined: Sat Jul 23, 2011 3:47 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
Has thanked: 311 times
Been thanked: 119 times

Post

The 3 big relays marked 'V230676-A3001-D142' are labelled A, B and C in the diagram

The function of relay A is the 'double injection relay' that's the main power relay to the whole BSM. If this relay is not energised, there is no power to the BSM module.

Relay B is the heater blower motor control and is associated with fuse F18 (40A)

Relay C is for the Power Steering and Engine ECU. The associated fuse is F8 (20A)


BSM relay functions
BSM relay functions
You can add an avatar to your account - Avatar or change your vehicle details - Car Bio or even add a signature to your posts - Signature. But this is not all you can do in the User Control Panel :)
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