Basic checks
Veepeak OBDCheck BLE
A Bluetooth LE adapter for reading standard engine codes and supported live data.
View on AmazonP25C1
Alternative Fuel Disable Signal Circuit
Moderate severity
The feedback signal that confirms the alt-fuel disable command was carried out is missing or out of range. The fuel system cannot verify that the gas circuit is shut.
The feedback signal that confirms the alt-fuel disable command was carried out is missing or out of range. The fuel system cannot verify that the gas circuit is shut.
Common causes
- high
Open feedback wire between relay and control module
One of the most commonly reported causes for this code — check this first.
Typical part cost: $130-660
- medium
Feedback contact in the disable relay corroded or stuck
A plausible cause — test and verify before replacing parts.
Typical part cost: $130-660
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P25C1.
Unlock causesFree forever · No credit card
First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
Get the full step-by-step diagnosis
Create a free Wrenchify account to unlock the rest for P25C1.
Unlock diagnosisFree forever · No credit card
Tools you may need
Already have a compatible scanner? Use it. If not, a Bluetooth OBD2 adapter can help you confirm engine codes and check supported live sensor data before replacing parts.
Regular diagnostics
vgate iCar Pro BLE 4.0
A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.
View on AmazonAnother option
OBDLink CX
A Bluetooth LE adapter to consider when comparing supported vehicles and diagnostic apps.
View on AmazonIllustrations shown, not product photos. Check vehicle, phone and app compatibility before buying. These adapters do not guarantee access to ABS, airbags or manufacturer-specific systems. Clearing a code does not repair the fault and can reset emissions readiness monitors.
As an Amazon Associate, Wrenchify earns from qualifying purchases. This supports the app at no extra cost to you.
Related codes
See related trouble codes
Create a free Wrenchify account to unlock the rest for P25C1.
Unlock related codesFree forever · No credit card
Frequently asked questions
What does P25C1 mean?
P25C1 means "Alternative Fuel Disable Signal Circuit". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P25C1?
open feedback wire between relay and control module; feedback contact in the disable relay corroded or stuck — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
Get the full P25C1 diagnosis for your vehicle
Year, make, model + step-by-step repair help — free plan included.