P2585: Fuel Additive Control Module Warning Lamp Request
The fuel additive control module asks for the additive-low warning lamp to be illuminated — the additive tank (Eolys/Cerine, used to lower DPF regen temperature) is approaching empty or has reached a service threshold. Continued driving without refilling will eventually disable DPF regeneration.
What P2585 means
P2585 is a generic OBD-II powertrain code in the fuel & air group.
- Check engine light
- Usually off
- Emissions-related
- No
- Limp mode possible
- Not typical
- Drive cycle to clear
- Not required
Get it fixed
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Common causes
- 01Additive tank low — service refill requiredMost likely
Can I drive with P2585?
Generally yes.
This fault is unlikely to affect how the car drives. Fix it when convenient.
Why we rate it low
- Does not normally turn on the check engine light
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P2585
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P2585. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Check for related codes first
Look for P2584. Related codes often share a cause; a circuit or sensor code usually needs fixing before a performance code like this one.
- 3
Check live data
Watch the related sensor and actuator readings in live data (Fuel additive tank) and compare them with expected values in the service information for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Additive tank low — service refill required. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.
P2585 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Moderate
- Good DIY job?
- Usually a shop job
Needs a scan tool and some experience with testing.
Parts and systems involved
- Fuel additive tank
P2585 FAQ
What does P2585 mean?
P2585 means “Fuel Additive Control Module Warning Lamp Request”. The fuel additive control module asks for the additive-low warning lamp to be illuminated — the additive tank (Eolys/Cerine, used to lower DPF regen temperature) is approaching empty or has reached a service threshold. Continued driving without refilling will eventually disable DPF regeneration.
Is P2585 serious? Can I keep driving?
We rate P2585 as low severity. Generally yes. This fault is unlikely to affect how the car drives. Fix it when convenient.
What causes P2585?
The most common causes, from most to least likely: Additive tank low — service refill required. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P2585?
Typical labor is about $65–$190 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P2585 myself?
DIY difficulty is moderate. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will P2585 clear itself?
If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.