Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer has found a problem with the part that heats up the liquid used to clean the car's exhaust. It's not working right.
The vehicle's computer has detected a low voltage in the circuit responsible for monitoring the heater of the diesel exhaust fluid (DEF) system.
The P248A code is triggered when the Engine Control Module (ECM) detects a low voltage condition in the reductant heater A sense circuit. This heater is part of the Selective Catalytic Reduction (SCR) system, which uses DEF to reduce emissions. The heater ensures the DEF remains liquid in cold conditions.
• Check Engine Light is on
• Poor emissions performance
• Possible reduction in engine power
• Faulty reductant heater
• Damaged wiring or connectors
• Faulty ECM
DEF: Diesel Exhaust Fluid
ECM: Engine Control Module
SCR: Selective Catalytic Reduction
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Test the reductant heater for proper operation.
• Repair or replace damaged wiring/connectors.
• Replace the reductant heater if faulty.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $600
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regularly inspect the DEF system.
• Ensure proper DEF fluid levels.
• Avoid driving in extremely cold conditions without proper maintenance.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Maintain regular service intervals for the DEF system.
Check with the vehicle manufacturer for emissions-related warranty coverage.
This code has become more common as SCR systems have been implemented in diesel vehicles to meet emission standards.
Moderate – It should be addressed soon to avoid potential emission issues.
Ignoring emission-related issues can lead to fines and increased pollution.
• Engine at operating temperature
• DEF system active
The reductant heater is typically located near the DEF tank or lines.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to poor emissions performance and potential engine power reduction.
Q: Can I drive my car with this code?
A: While the car may still be drivable, it is advisable to address the issue to ensure proper emissions control.
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