Fuel Additive Control Module
Meters a catalytic additive into the fuel tank on diesels that use a fuel-borne catalyst to help the particulate filter regenerate. Soot ignites at a temperature a diesel exhaust does not reliably reach; most manufacturers bridge that gap by injecting extra fuel to raise exhaust temperature, but some instead dose a cerium or iron compound into the fuel, which travels through combustion into the soot and lowers the temperature at which it will burn.
The module has no warning lamp of its own, so it asks the engine module to light one — which is why its faults surface as P2584 and P2585 on a basic reader, with the actual detail stored where that reader cannot see it.
The property that costs owners money is that the additive is a consumable. It sits in its own tank, is used up, and needs refilling roughly every 70,000 to 100,000 miles depending on the vehicle. It is not part of a normal service, both owners and workshops are frequently unaware of it, and when it runs out regeneration stops completing properly — so the filter loads up over months toward a far more expensive failure. The module also counts consumption rather than measuring it, so the level must be reset after a refill or it still reads empty.
Also known as: additive control module, eolys module, fap additive module, fuel borne catalyst module, additive ecu, dpf additive module
Referenced by 4 codes
Codes involving this component (4)
Other components in Exhaust and Emissions
- Oxygen Sensor 326
- EGR Valve 150
- Catalytic Converter 142
- NOx Sensor 118
- Reductant Injector 107
- Exhaust Gas Temperature Sensor 95
- Reductant Tank 95
- Diesel Particulate Filter 76
- SCR Catalyst 65
- EGR Cooler 62
- Exhaust Gas Differential Pressure Sensor 58
- Fuel Tank Pressure Sensor 58
- Exhaust Pressure Control Valve 56
- Reductant Heater 55
- Reductant Pump 51
- EVAP Vent Valve 43
- Exhaust Aftertreatment Fuel Injector 42
- Charcoal Canister 33
- EGR Position Sensor 32
- Secondary Air Injection Pump 32
- Reductant Temperature Sensor 29
- EVAP Leak Detection Pump 29
- EVAP Purge Valve 27
- Particulate Matter Sensor 24
- Reductant Control Module 24
- Reductant Level Sensor 23
- Secondary Air Switching Valve 22
- EGR Temperature Sensor 21
- Secondary Air Check Valve 21
- Catalyst Heater 20
- Catalyst Temperature Sensor 20
- Fuel Filler Cap 18
- EGR Cooler Bypass Valve 16
- Reductant Quality Sensor 16
- Exhaust Back Pressure Sensor 15
- Purge Flow Sensor 13
- Direct Ozone Reduction Catalyst 13
- EGR Vacuum Solenoid 9
- Fuel Vapour Temperature Sensor 5
- Fuel Additive Tank 4
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