What Does P2585 Mean?
The fuel additive control module is requesting illumination of a dedicated warning lamp separate from the MIL. This alerts the driver to service the fuel additive system before more severe restrictions occur.
Common Causes
45%
Low fuel additive level requiring refill
25%
Poor quality or contaminated fuel additive detected
15%
Faulty additive dosing pump or injector
10%
Additive system heater failure in cold climate
5%
Additive control module software issue or calibration
Diagnostic Steps
1
Step 1: Check additive tank level and top off with fresh, manufacturer-approved fluid
2
Step 2: Access additive system menu in scan tool to view detailed system status and fault memory
3
Step 3: Test additive quality with refractometer and verify it meets specification
4
Step 4: Check additive pump operation by commanding injection test with scan tool
5
Step 5: Verify all additive system heaters are functioning in cold weather operation
Estimated Repair Cost
$100 - $1,800
Parts + labor, varies by vehicle and location
The fuel additive control module is requesting illumination of a dedicated warning lamp separate from the MIL. This alerts the driver to service the fuel additive system before more severe restrictions occur.
The most common cause of P2585 (Fuel Additive Control Module Warning Lamp Request) is: Low fuel additive level requiring refill
Typical repair costs for P2585 range from $100 to $1,800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Warning stage before vehicle enters limp mode or no-restart condition. Immediate service prevents being stranded. No direct safety risk but should be addressed promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2585 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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