P0403 on Citroen
Exhaust Gas Recirculation Circuit Malfunction
P0403 on Citroen vehicles indicates exhaust gas recirculation circuit malfunction. Au7o has documented this code across 1 Citroen model — most commonly on C4. 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. Typical repair costs on Citroen range from $150 to $500, depending on the specific model and root cause.
Common Causes of P0403
- •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
P0403 on Citroen by Model
Citroen C4(1 issue)
- EGR Valve Carbon Buildup2004-2021
The C4 diesel EGR valve accumulates carbon deposits that cause it to stick open or closed. The blocked EGR increases exhaust emissions, causes rough idle, and can trigger the engine management warning light.
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View P0403 across all makes →Frequently Asked Questions
What does P0403 mean on Citroen?▼
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 Citroen specifically, this code is documented across 1 model.
What causes P0403 on Citroen vehicles?▼
Common causes on Citroen: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0403 on a Citroen?▼
Repair costs on Citroen range from $150 to $500, depending on the specific model and root cause.
Which Citroen models have P0403 documented?▼
Au7o has documented P0403 on 1 Citroen model: C4.