Citroën Aircross Fuse Diagram: Engine Compartment Fuse Box Location and Critical Functions

Introduction to the Electrical Management System of the Citroën Aircross

The Citroën Aircross, built on PSA’s PF1 platform, shares many of its electric features with the C3 and C4. However, the power management in the engine compartment is centralized in the… BSM (Boîtier de Servitude Moteur)This component acts as a fuse box and power unit. A blown fuse here is rarely an isolated event; it’s usually a symptom of a shorted component or a specific overload in the wiring harness. Owners frequently report the car stalling unexpectedly or refusing to start, often accompanied by the message “Anti-theft System Fault” or “Engine Failure.”

Location and Access to the BSM (Engine Bay Housing)

In the Aircross, the engine fuse box is located on the upper right side (driver’s side), just behind the battery. To access it, you need to remove the protective plastic cover. There are two levels of fuses: surface fuses (immediately accessible) and surface fuses (immediately accessible). Maxi fuses (MF), which are hidden on the underside of the circuit board or on a specific trace below the main unit.

Critical Fuse Table (BSM – Version R01/R05)

Below, I list the fuses that most commonly cause sudden engine stalls in the Aircross (1.6 16v VTi or Flex engines):

Common Causes of Burns and Technical Diagnosis

When a 20A or 30A fuse in the BSM blows, the mechanic should investigate beyond simple replacement. In the Aircross, the most likely causes include:

• Short circuit in the lambda sensor wiring harness: The wiring from the pre-catalyst lambda sensor often rubs against the engine mount or melts in the intake manifold, causing immediate F15 combustion.
• Fuel Pump Seizure: The increased current (amperage) due to wear on the pump refill burns out the F15 or damages the internal relay of the BSM.
• Short-circuited starting solenoid: If the F8 burns out, the problem is usually in the starter motor solenoid, specifically in models equipped with a Valeo starter motor.

Related DTC Codes (Scanner)

When performing diagnostics via OBD-II (using Lexia/Diagbox or a multi-brand scanner), the following codes indicate problems with the BSM power supply:

• P0200: Injector circuit fault (Check F10).
• P0685: ECU main relay – Open circuit (Internal problem in BSM or F1).
• P0443: Canister purge valve failure (May be associated with the same F15 busbar).
• U1108: Communication failure with the engine ECU (usually due to lack of positive power supply).

Step-by-Step Diagnosis

1. Visual Inspection: Before testing, check for signs of oxidation (verdigris) on the BSM connectors. Water entering through a clogged grill drain is fatal to the board.
2. Continuity Test: Using a multimeter set to the continuity (beep) setting, test the fuses one by one without removing them (use the test points on top of the fuse).
3. Load Verification at Output: If fuse F15 blows when you turn the key, disconnect the fuel pump and the lambda sensors. If it stops blowing, reconnect them one by one until you isolate the culprit.
4. Analysis of Internal Relays: The BSMs in the Aircross have relays soldered internally. If the fuse is good, but there is no 12V at the pump, relay R1 on the board probably has stuck or carbonized contacts.

Solution and Repair

If the problem is only the fuse, it should be replaced with one of the same amperage (standard Mini or JCase in Maxifuses).. Never use fuses with a higher amperage rating.Because in the Aircross this can cause the main wiring harness to melt.

If the fault is internal to the BSM (frequently caused by water infiltration), repair of the board is possible at companies specializing in embedded electronics, but replacement with a new or semi-new part of the same reference is the definitive solution.

OEM Parts and Reference Codes

There are different versions of BSM for the Aircross, depending on the accessory package (fog lights, sunroof, etc.):

• BSM R01: 6500GR (Common part in entry-level versions).
• BSM R05 / R09: 9666700480 / 6500GT (Full versions).
• Alternative Reference: Magneti Marelli or Delphi (original manufacturers for PSA).

Costs and When to Seek a Specialist

The cost of a set of fuses is negligible (R$ 20.00). However, a new BSM at the dealership can vary between R$ 1,800.00 and R$ 3,200.00. In the used market (certified salvage yards), they cost between R$400.00 and R$800.00.. Attention: BSM does not require coding (it’s plug-and-play), unlike BSI (dashboard), which is paired with the key and ECU.

Take it to the dealership or a French-specialized workshop if the problem persists after replacing the fuse, or if there are CAN network errors (codes starting with U), which require the use of Diagbox software for fault mapping.

Electrical Fault Prevention

To avoid headaches with your Aircross’s BSM:

• Keep the grill drains (below the windshield) clean at all times. Water that accumulates there overflows directly into the fuse box.
• Avoid installing accessories (Xenon, powerful sound system) that draw current directly from the BSM without using external relays and dedicated protective fuses.
• Check the battery status; voltage drops below 10.5V during startup cause phantom errors in the BSM and generate communication DTCs.