P0403 on Toyota: How to Diagnose & Fix
Exhaust Gas Recirculation Circuit Malfunction
1 Toyota model · 1 documented issue · $150-$600 repair
P0403 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…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
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
P0403 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 P0403 mean on a Toyota?
P0403 stands for "Exhaust Gas Recirculation Circuit Malfunction." This emissions code indicates a malfunction in the exhaust gas recirculation (EGR) control circuit. The EGR system routes a small amount of exhaust back into the intake to lower combustion temperatures and reduce nitrogen-oxide emissions, and the computer commands the EGR valve open and closed through this circuit. The code sets when the electrical control signal to the EGR valve or its solenoid is out of the expected range — for example, an open, short, or a commanded change that doesn't produce the right feedback. It generally points to an electrical or wiring problem in the EGR control circuit, or the EGR valve/solenoid itself, rather than carbon clogging alone. On Toyota it is documented across 1 model: Prius V.
What are the most common causes of P0403?
The most common causes of P0403 are: Faulty EGR valve or EGR solenoid, Damaged wiring or connector in the EGR control circuit, Open or short in the EGR control wiring, Corroded or loose EGR connector, Blown fuse or lost power supply to the EGR circuit, Carbon buildup binding the EGR valve, Faulty engine control module or driver circuit. The specific cause varies by vehicle.
How much does it cost to fix P0403 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 P0403 on a different make?
View P0403 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.