Cause
Fuel additive tank empty
The additive tank empty on a vehicle that doses a catalyst additive into the fuel. Some diesels use an additive to lower the temperature at which the particulate filter regenerates, held in its own small tank and metered in at each refuelling — and it is a consumable that many owners do not know exists.
An empty tank means regeneration needs a higher temperature than the vehicle can readily reach, so regenerations become harder to complete, the filter loads, and the codes that follow name the filter rather than the additive. A filter loading on a vehicle whose additive tank is empty is a consequence.
It is not a service item on most schedules, being refilled at a long interval, so it is missed. Check the additive level and the dosing counter together — and note that refilling alone is often not enough, since the counter that tracks remaining additive has to be reset for the module to believe the tank is full.
Typically a moderate job.
Codes this can cause (2)
Codes where this is a likely explanation first, rather than merely a possible one.
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Others who found this
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about Fuel additive tank empty.