Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means the car's computer is having trouble reading how much special fluid, called DEF, is left in the tank. It's like the car can't tell how full the tank is.
The P203A code indicates a problem with the electrical circuit of the reductant level sensor, which monitors the amount of diesel exhaust fluid (DEF) in the vehicle's tank.
The reductant level sensor is part of the vehicle's selective catalytic reduction (SCR) system, which reduces emissions. This sensor sends a signal to the engine control module (ECM) about the DEF level. If the ECM detects a fault in the sensor's circuit, it triggers the P203A code.
• Check engine light is on
• Reduced engine performance
• Incorrect DEF level readings
• Faulty reductant level sensor
• Wiring issues such as open or short circuits
• Defective ECM
DEF: Diesel Exhaust Fluid, a fluid used in diesel engines to reduce emissions.
ECM: Engine Control Module, the computer that manages engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors of the reductant level sensor for damage.
• Test the reductant level sensor for proper operation.
• Replace the reductant level sensor if faulty.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-250
• Chevrolet Silverado
• Dodge Ram 2500
• Regularly check and maintain DEF levels.
• Inspect wiring and connectors periodically.
• Use quality DEF fluid to prevent sensor contamination.
Sensor Issue
• Do not ignore the check engine light.
• Have the vehicle inspected by a professional mechanic.
• Keep DEF tank filled to avoid triggering the sensor.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code has become more common with the increased use of SCR systems in diesel vehicles to meet emission standards.
Moderate – It's important to address this issue to ensure proper vehicle emissions and performance.
Ignoring emission-related issues can lead to fines and increased emissions, which are harmful to the environment.
• Vehicle must be running.
• DEF tank should be at least partially filled.
The reductant level sensor is typically located in the DEF tank, which is usually near the rear of the vehicle.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to reduced engine performance and increased emissions, potentially resulting in legal penalties.
Q: Can I fix this issue myself?
A: If you have basic mechanical skills and tools, you might be able to inspect and replace the sensor or repair wiring, but professional diagnosis is recommended.
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