Iveco 153 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Low pressure fuel rail

The engine control module detects that the actual fuel pressure in the common rail is lower than the requested/target minimum pressure, preventing adequate fuel delivery.

• Iveco Daily
• Iveco Stralis
• Iveco Eurocargo

1. 1

   Monitor live data using a diagnostic scanner to compare actual fuel rail pressure versus requested rail pressure, and check the fuel pressure regulator (DRV/SCV) duty cycle

2. 2

   Perform a low-pressure circuit test by connecting a manometer to check the fuel pressure supply from the lift pump

3. 3

   Conduct an injector leak-off (return flow) test hot and cold to check if one or more injectors are bypassing too much fuel back into the return line

4. 4

   Visually inspect the main fuel filter, pre-filter, and the micro-filter on the high-pressure pump inlet for blockages, swarf, or contamination

1. 1

   Address the Low-Pressure System

   Replace the main fuel filter and pre-filter. Ensure there are no air leaks in the low-pressure fuel lines between the tank and the high-pressure pump.

2. 2

   Test and Replace Faulty Injectors

   If the leak-off test reveals excessive return flow from specific cylinders, remove and refurbish or replace the faulty fuel injectors.

3. 3

   Inspect the Fuel Pressure Regulator (MPROP/ZVC)

   Remove the fuel pressure regulator (often located on the high-pressure pump). Inspect the fine metal cone filter on the tip for metal shavings (which indicates pump failure) or dirt. If contaminated or electrically failing, replace the regulator.

4. 4

   Check the High-Pressure Pump

   If the lift pump is supplying adequate pressure, the injectors are not leaking off, and the regulator is new, the high-pressure fuel pump (e.g., Bosch CP1 or CP3) is likely failing to generate pressure and must be replaced.

5. 5

   Clear and Relearn

   Clear the fault codes from the EDC memory. If required by the specific ECU, perform a relearn procedure for the new components, then road test the vehicle under load to ensure the rail pressure meets requested values.