A failed EGR position sensor (often built into the EGR valve). An open or shorted wire. A missing 5-volt reference.

P0405 Exhaust Gas Recirculation Sensor "A" Circuit Low

Q: What does P0405 mean?

P0405 means the EGR position or pressure sensor's signal is too low, usually wiring or a failed sensor. The EGR position or pressure feedback sensor's signal is too low, usually from a wiring fault or a failed sensor.

Emissions

P0405 means the EGR position or pressure sensor's signal is too low, usually wiring or a failed sensor.

The EGR position or pressure feedback sensor's signal is too low, usually from a wiring fault or a failed sensor.

Can I keep driving? Yes, but get it fixed soon.

Usually drivable; the engine computer may stop using EGR. Get it fixed soon.

Common causes

A failed EGR position sensor (often built into the EGR valve)
An open or shorted wire
A missing 5-volt reference

Symptoms

Check-engine light
Sometimes pinging under load

What to check first

Inspect the EGR valve's connector and wiring.
Check the 5-volt reference and ground.
Watch the EGR position reading with a scan tool while commanding the valve.
Replace the valve or sensor if wiring is good.

What does P0405 mean on your vehicle?

The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.

Ask iRepair about P0405

No scanner? Most auto parts stores read check-engine codes for free.

Related codes

General guidance for P0405 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.