P203C Fault Code

Reductant Level Sensor Circuit Low

• What does that mean?
• Symptoms
• Causes
• Solutions

The P203C fault code indicates a problem with the reductant level sensor circuit in the vehicle. This sensor is responsible for monitoring the level of diesel exhaust fluid (DEF) in the tank, which is critical for reducing emissions in diesel engines. When this sensor malfunctions or its circuit experiences issues, it can trigger a warning in the vehicle's onboard diagnostic system.

What are the symptoms of the P203C code?

When the P203C code is triggered, drivers may experience:

• Warning lights on the dashboard indicating a DEF malfunction.
• Reduced engine performance due to a limp mode activated by the vehicle’s computer.
• Increased emissions, potentially leading to a failed emissions test.
• An unpleasant odor of diesel exhaust fluid if there is a significant leak.

What causes the P203C code?

Potential causes for a P203C fault code include:

• A faulty reductant level sensor that is unable to provide accurate readings.
• Damaged wiring or connectors in the sensor circuit that affect communication.
• Low levels of diesel exhaust fluid (DEF) in the tank, causing the sensor to send incorrect signals.
• Corrosion or contamination affecting the sensor's performance.

How to fix P203C?

To resolve the P203C fault code, the following steps may be taken:

• Inspect and replace the reductant level sensor if it is found to be faulty.
• Check and repair any damaged wiring or connectors in the circuit.
• Ensure that the diesel exhaust fluid (DEF) tank is filled to the proper level.
• Clear the fault code from the vehicle's computer and perform a test drive to verify that the issue is resolved.