P203D Fault Code

Reductant Level Sensor Circuit High

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

The P203D fault code indicates that there is an issue with the reductant level sensor circuit, specifically that it is reporting a high signal. This code is part of the vehicle's emissions control system, which monitors the level of diesel exhaust fluid (DEF) necessary for proper operation of the selective catalytic reduction (SCR) system. High readings from the sensor may prevent the SCR system from functioning efficiently, leading to increased emissions and potential engine performance issues.

What are the symptoms of the P203D code?

Drivers may experience the following symptoms when the P203D code is present:

• Activation of the check engine light on the dashboard.
• Poor engine performance or reduced power.
• Increased exhaust emissions and failure to pass emissions tests.
• Potential vehicle limp mode, where performance is significantly limited for safety.

What causes the P203D code?

This fault code can be triggered by several factors, including:

• A malfunctioning reductant level sensor that is sending an incorrect signal.
• Poor electrical connections or wiring issues within the sensor circuit.
• Contamination or damage to the DEF itself, affecting sensor readings.
• A defective engine control module (ECM) that misinterprets sensor data.

How to fix P203D?

To address the P203D fault code, the following steps are recommended:

• Inspect the electrical connections and wiring for the reductant level sensor, looking for signs of damage or corrosion.
• Test the reductant level sensor using a multimeter to check for proper function and replace it if necessary.
• Check the DEF for contamination and replace it if the fluid is not up to specifications.
• Clear the code and perform a road test to ensure that the issue is resolved and the check engine light does not reappear.