What does P0403 mean?

The ECU found an electrical fault in the EGR valve control circuit.

Is P0403 the same as P0401?

No. P0401 is about flow; P0403 is about the electrical control circuit.

Emission control

P0403 — Exhaust Gas Recirculation Control Circuit

The ECU detected an electrical fault in the EGR valve control circuit, such as an open or short in the solenoid or motor. The EGR system cannot be controlled properly.

Severity: Medium

Common causes

Faulty EGR valve solenoid or motor
Damaged wiring or loose connector
Blown fuse or power supply issue
Heat or carbon damage to the valve
Engine control module driver fault (rare)

Symptoms

Rough idle
Poor performance
Failed emissions test
Check engine light

How to check

Check the EGR valve connector and wiring
Measure the solenoid resistance and the supply voltage
Command the valve with a scan tool and listen/feel for operation
Replace the valve if its internal circuit is faulty

Can you keep driving?

Usually drivable. Repair it at a convenient time to avoid emissions failure and possible idle problems.

Frequently asked questions

What does P0403 mean?: The ECU found an electrical fault in the EGR valve control circuit.
Is P0403 the same as P0401?: No. P0401 is about flow; P0403 is about the electrical control circuit.

General reference information. It does not replace a diagnosis on your own vehicle. The same code can have different causes depending on make, model year and engine; check the manufacturer's documentation or ask a technician with a scan tool.