Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This means there's a problem with a part of the car that helps keep a special fluid warm. The car is saying it can't sense the heater working like it should.
The code P248C indicates that the vehicle's computer has detected a low voltage condition in the circuit that monitors the second reductant heater.
The reductant heater is part of the selective catalytic reduction (SCR) system, which uses a fluid called DEF (Diesel Exhaust Fluid) to reduce emissions. This heater ensures the DEF stays at the right temperature. The 'B' circuit refers to the second heater in the system. A low signal means the voltage is below the expected range, indicating a potential issue with the heater or its circuit.
• Check Engine Light is on
• Poor vehicle performance
• Increased emissions
• Possible DEF system warnings
• Faulty reductant heater B
• Open or shorted wiring in the heater circuit
• Poor electrical connection at the heater
• Faulty engine control module (ECM)
Reductant: A substance used to reduce emissions in a vehicle, often Diesel Exhaust Fluid (DEF).
SCR: Selective Catalytic Reduction, a system that reduces emissions in diesel engines.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the reductant heater B for proper resistance.
• Check for proper voltage and ground at the heater connector.
• Repair or replace damaged wiring or connectors.
• Replace the reductant heater B if faulty.
• Clear the code and test drive to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regularly inspect and maintain the DEF system.
• Ensure proper DEF fluid levels.
• Check for corrosion or damage in electrical connections.
Sensor Issue
• Do not ignore the Check Engine Light.
• Address the issue promptly to avoid increased emissions.
• Consult a professional if unsure about repairs.
Check with your vehicle manufacturer for specific warranty coverage related to emissions and DEF components.
This code is relatively common in diesel vehicles equipped with SCR systems, as the DEF system is crucial for emissions control.
Moderate – While the vehicle may still operate, emissions may be higher, and performance could be affected.
Operating a vehicle with a malfunctioning emissions system may violate emissions laws and could lead to fines.
• Engine running and warmed up
• DEF system active
The reductant heater is typically located near the DEF tank or lines, under the vehicle.
Q: Can I drive with a P248C code?
A: While you can drive with this code, it's not recommended as it can lead to increased emissions and potential damage to the DEF system.
Q: What is a reductant heater?
A: A reductant heater keeps the Diesel Exhaust Fluid (DEF) at the right temperature to ensure it works properly in reducing emissions.
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