P204F on Chevrolet
Reductant System Incorrect Quantity
P204F on Chevrolet vehicles indicates reductant system incorrect quantity. Au7o has documented this code across 1 Chevrolet model — most commonly on Silverado 3500HD. This code is set on diesel SCR-equipped vehicles when the reductant (diesel exhaust fluid / DEF) system delivers an incorrect quantity of DEF, meaning the actual dosing or pressure doesn't match what the computer commanded. The reductant system pumps and injects DEF into the exhaust so the SCR catalyst can break down NOx emissions, and the computer monitors pressure and dosing performance. When it sees too much or too little fluid being delivered, or pressure that's out of range, it flags this performance code. Typical roots are a clogged or failing DEF pump, contaminated fluid, a faulty pressure sensor, or a bad injector. Typical repair costs on Chevrolet range from $300 to $1,500, depending on the specific model and root cause.
Common Causes of P204F
- •Contaminated or poor-quality diesel exhaust fluid (DEF)
- •Faulty reductant (DEF) pressure sensor
- •Clogged DEF pump filter or weak/failing DEF pump
- •Faulty or clogged reductant injector
- •Leaking, cracked, or loose DEF lines/clamps
- •Crystallized DEF buildup blocking the system
- •Failed reductant/SCR control module
- •Wiring or connector faults in the reductant system
P204F on Chevrolet by Model
Chevrolet Silverado 3500HD(1 issue)
- DEF System Malfunction and Reduced Power2011-2025
Diesel exhaust fluid (DEF) system components fail causing "Service Exhaust Fluid System" warnings and eventual speed limiting to 65 mph then 5 mph. DEF injector, heater, or quality sensor most common failure points.
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View P204F across all makes →Frequently Asked Questions
What does P204F mean on Chevrolet?▼
P204F stands for "Reductant System Incorrect Quantity." This code is set on diesel SCR-equipped vehicles when the reductant (diesel exhaust fluid / DEF) system delivers an incorrect quantity of DEF, meaning the actual dosing or pressure doesn't match what the computer commanded. The reductant system pumps and injects DEF into the exhaust so the SCR catalyst can break down NOx emissions, and the computer monitors pressure and dosing performance. When it sees too much or too little fluid being delivered, or pressure that's out of range, it flags this performance code. Typical roots are a clogged or failing DEF pump, contaminated fluid, a faulty pressure sensor, or a bad injector. On Chevrolet specifically, this code is documented across 1 model.
What causes P204F on Chevrolet vehicles?▼
Common causes on Chevrolet: Contaminated or poor-quality diesel exhaust fluid (DEF), Faulty reductant (DEF) pressure sensor, Clogged DEF pump filter or weak/failing DEF pump, Faulty or clogged reductant injector, Leaking, cracked, or loose DEF lines/clamps. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P204F on a Chevrolet?▼
Repair costs on Chevrolet range from $300 to $1,500, depending on the specific model and root cause.
Which Chevrolet models have P204F documented?▼
Au7o has documented P204F on 1 Chevrolet model: Silverado 3500HD.