---
title: "P204C Reductant Pressure Sensor Circuit Low"
slug: p204c
collection: obd2-codes
code: P204C
url: https://fixmycar.pk/obd2-code-list/p204c/
---
The OBD-II code **P204C** signifies a low voltage condition in the Reductant Pressure Sensor circuit, a critical component of the Selective Catalytic Reduction (SCR) system in diesel vehicles. This sensor monitors the pressure of Diesel Exhaust Fluid (DEF), ensuring proper injection to reduce harmful nitrogen oxide (NOx) emissions. A low voltage reading can result from issues like a faulty sensor, damaged wiring, or problems within the SCR system.

Symptoms may include an illuminated check engine light, reduced engine performance, and increased emissions . Prompt diagnosis and repair are essential to maintain vehicle efficiency and comply with emission standards.