When a Bosch VP30 or VP44 pump from another vehicle is fitted to a Ford diesel —Focus 1.8 TDDi, Transit or Transit Connect TDDi— the engine commonly starts and cuts out immediately. In most cases the pump is not faulty: its PSG5 control unit has been locked by the immobiliser. In workshops and forums this situation is often searched for as “immo off”.
Why the unit locks
On these Fords, the pump’s PSG5 control unit is paired with the vehicle it is fitted to. When it does not recognise the vehicle, the control unit itself blocks injection. The immobiliser detects the lock and reports it through the red warning light on the centre console.
This is why the lock appears when a pump is moved from one vehicle to another, when a used or remanufactured pump that keeps its previous pairing is fitted, or when a PSG5 control unit taken from another pump is fitted.
How to recognise it
- The engine starts and cuts out immediately. This is a very characteristic symptom.
- At ignition on, the red warning light stays on or flashes, instead of lighting briefly and going out.
- With the HC-VCI interface connected to the pump, the immobiliser state reads as locked.
Reading the warning light is covered in detail in Ford VP30 and VP44: the immobiliser warning light and a locked pump control unit.
Solutions
Unlocking at an authorised Ford dealer
The pump control unit can be unlocked at an authorised Ford dealer.
Unlocking with the HC-VCI
The HC-VCI diagnostic interface connects at the pump’s own connector, reads the immobiliser state and unlocks the control unit in a few seconds. The control unit is returned to a virgin state, so the pump can be fitted to another vehicle. The function covers all Ford pumps with a PSG5 control unit.
Replacement with the HC-PSG5
If the control unit is also faulty, the HC-PSG5 replaces it. HC-PSG5 units for Ford do not lock: they are supplied coded and calibrated for the pump number and need no pairing or unlocking when fitted.
Before fitting a used pump
The HC-VCI reads the immobiliser state with the pump at rest, including on the bench. Checking it before fitting allows the control unit to be unlocked in advance and avoids removing the pump a second time.
References: HC-PSG5 compatibility and references. Enquiries: contact.
Herlic Components — OEM-equivalent diesel injection electronics, engineered in Europe.
