Peugeot/Citroen Engine Control Unit Pairing

Supported coding features by PSACOM diagnostic tool https://www.obdtester.com/psacom

Engine Control Unit Pairing

What it does

• Pairs the engine control unit (ECU) with the vehicle security system
• Synchronizes ECU with:
• BSI (Body System Interface)
• Immobilizer
• Allows engine start and normal operation

When it is required

• After replacing the engine control unit
• After replacing or reprogramming the BSI
• After immobilizer or key-related repairs
• When engine does not start due to pairing errors

Conditions that must be met

• Vehicle stationary
• Ignition ON
• Stable battery voltage
• Valid security code (PIN) available
• Diagnostic tool connected and authorized

What happens during pairing

• ECU and BSI exchange security credentials
• Immobilizer authorization is learned
• VIN and configuration data may be synchronized
• Engine start authorization is enabled

If pairing is not performed

• Engine will not start
• Immobilizer warning may be active
• Fault codes related to ECU/BSI communication
• Vehicle remains immobilized

After pairing

• Verify successful engine start
• Check immobilizer and ECU status in diagnostics
• Confirm no related warning lights remain
• Clear any stored fault codes

Coverage in PSACOM