
Basic checks
Veepeak OBDCheck BLE
A Bluetooth LE adapter for reading standard engine codes and supported live data.
View on AmazonAlternative Fuel Disable Control Circuit High
Voltage on the alternative-fuel disable control line is above the expected window. Often a short to battery upstream of the relay or a stuck-on driver in the control module.
Voltage on the alternative-fuel disable control line is above the expected window. Often a short to battery upstream of the relay or a stuck-on driver in the control module.
One of the most commonly reported causes for this code — check this first.
Typical part cost: $130-550
A plausible cause — test and verify before replacing parts.
Typical part cost: $130-550
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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.

Basic checks
A Bluetooth LE adapter for reading standard engine codes and supported live data.
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Regular diagnostics
A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.
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Another option
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.
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P25BF means "Alternative Fuel Disable Control Circuit High". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
disable control wire shorted to a b+ supply; output driver stuck on inside the control module; connector pins corroded - high contact resistance — 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.
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.
Year, make, model + step-by-step repair help — free plan included.