AutoCodes – RAM – P20F4 RAM

P20F4 RAM Code - Reductant Consumption Too Low

Quick Answer

The Powertrain Control Module (PCM) monitors the Diesel Exhaust Fluid (DEF) consumption by comparing the DEF pressure in the supply line to the known DEF Supply Pump volume. Common causes include Low Diesel Exhaust Fluid Level, Contaminated Diesel Exhaust Fluid, Diesel Exhaust Fluid (DEF) Pressure Line Damage. 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: P20F4 RAM indicates Reductant Consumption Too Low.
Common causes: Common causes include Low Diesel Exhaust Fluid Level, Contaminated Diesel Exhaust Fluid, Diesel Exhaust Fluid (DEF) Pressure Line Damage.
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 353

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 May 18, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P20F4 RAM Description

The Powertrain Control Module (PCM) monitors the Diesel Exhaust Fluid (DEF) consumption by comparing the DEF pressure in the supply line to the known DEF Supply Pump volume. This rationality comparison will detect DEF consumption high or low failures. The PCM will illuminate the MIL light immediately after the diagnostics runs and fails. The DEF injection into the aftertreatment system will be disabled.

OBDII Code P20F4 RAM - Reductant Consumption Too Low - AutoCodes.com — P20F4 RAM Code - Reductant Consumption Too Low

What does this mean?

What are the Possible Causes of the DTC P20F4 RAM?

Low Diesel Exhaust Fluid Level
Contaminated Diesel Exhaust Fluid
Diesel Exhaust Fluid (DEF) Pressure Line Damage
DEF Injector Physically Stuck Open
Faulty DEF Supply Pump Assembly

How to Fix the DTC P20F4 RAM?

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 P20F4 RAM 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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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.