AutoCodes – Generic – P204B

P204B Code - Reductant Pressure Sensor Circuit Range/Performance

Quick Answer

The Reductant Pressure Sensor, located in the Reductant Pump and Sensor Assembly, responds to pressure changes in the reductant system. Common causes include Faulty Reductant Pump and Sensor Assembly, Reductant Pump and Sensor Assembly harness is open or shorted, Reductant Pump and Sensor Assembly circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P204B indicates Reductant Pressure Sensor Circuit Range/Performance.
Common causes: Common causes include Faulty Reductant Pump and Sensor Assembly, Reductant Pump and Sensor Assembly harness is open or shorted, Reductant Pump and Sensor Assembly circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 28,546

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 21, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P204B Description

The Reductant Pressure Sensor, located in the Reductant Pump and Sensor Assembly, responds to pressure changes in the reductant system. The Reductant Control Module supplies 5 V to the reductant pressure sensor on the 5 V reference circuit and provides a ground on the low reference circuit. The reductant pressure sensor provides a signal to the Reductant Control Module on the sensor signal circuit relative to the pressure changes in the reductant system. The Engine Control Module (ECM) is
connected to the Reductant Control Module via the Controller Area Network (CAN) bus. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the reductant pressure sensor signal is open or shorted to ground.

OBDII Code P204B - Reductant Pressure Sensor Circuit Range/Performance - AutoCodes.com — P204B Code - Reductant Pressure Sensor Circuit Range/Performance

What does this mean?

What are the Possible Causes of the DTC P204B?

Faulty Reductant Pump and Sensor Assembly
Reductant Pump and Sensor Assembly harness is open or shorted
Reductant Pump and Sensor Assembly circuit poor electrical connection
Faulty Reductant Control Module

How to Fix the DTC P204B?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P204B code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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Information for Specific Makes

P204B Chevrolet — Reductant Pressure Sensor Circuit Range/Performance
P204B Dodge — Reductant Pressure Sensor Circuit Range/Performance
P204B Ford — Reductant Pressure Sensor Circuit Range/Performance
P204B GMC — Reductant Pressure Sensor Circuit Range/Performance

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.