P0404 on Toyota: How to Diagnose & Fix
Exhaust Gas Recirculation Circuit Range/Performance
1 Toyota model · 1 documented issue · $150-$600 repair
P0404 on Toyota by model: symptoms, diagnosis and fix
The Prius V uses an EGR (Exhaust Gas Recirculation) cooler that produces condensation during short trips and cold weather driving. This condensation mixes with exhaust gases to form carbon deposits in the intake manifold and on the intake valves. Over time, the carbon buildup restricts airflow, causing rough idle and reduced fuel economy. The EGR valve itself can also become stuck from carbon accumulation. This is more prevalent in cold climate Prius V models driven primarily for short trips.
Common Symptoms
- Rough idle especially in cold weather
- Check engine light with EGR-related codes
- Reduced fuel economy (3-5 MPG drop)
- Hesitation during acceleration
- Engine stalling at idle
How to Fix
Clean the EGR valve and intake manifold ports using a carbon solvent (CRC GDI IVD Intake Valve & Turbo Cleaner). For severe buildup, the intake manifold must be removed for manual cleaning. Replace the EGR valve if it's stuck open or closed. Extended highway driving periodically helps burn off light deposits. Some owners install a catch can on the EGR line to trap condensation.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Toyota 04004-58137 EGR valve kit
replace a bulletin-confirmed sticking EGR valve as part of the complete Toyota repair procedure Fitment/availability: Toyota bulletin repair kit for the specified sticking-EGR-valve condition on covered early Prius/Prius v/Prius PHV appl…
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Owner tips & cautions
- TipTake the Prius V on a 20+ minute highway drive weekly to bring the engine to full operating temperature — this helps burn off EGR condensation and deposits
- TipClean the EGR valve every 60,000 miles as preventive maintenance — a $150 cleaning prevents a $600 intake manifold removal job later
P0404 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0404 mean on a Toyota?
P0404 stands for "Exhaust Gas Recirculation Circuit Range/Performance." This code means the exhaust gas recirculation (EGR) system isn't performing within its expected range. The EGR valve routes a metered amount of exhaust gas back into the intake to lower combustion temperatures and reduce nitrogen-oxide emissions, and the computer monitors the valve's actual position versus what it commanded. When the valve sticks, moves incorrectly, or the feedback doesn't match the command, P0404 sets. This can cause rough idle, hesitation, pinging, and increased emissions. On Toyota it is documented across 1 model: Prius V.
What are the most common causes of P0404?
The most common causes of P0404 are: Carbon buildup clogging the EGR valve or passages, Sticking or failed EGR valve, Faulty EGR position sensor, Corroded or loose EGR connector, Damaged or shorted EGR wiring, Vacuum leak or failed vacuum control (on vacuum-operated systems), Clogged EGR cooler or tubes, Faulty PCM/ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0404 on a Toyota?
Published repair estimates on Toyota range from $150 to $600 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0404 on a different make?
View P0404 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.