P0405 EGR sensor A circuit low
What P0405 means
The engine control unit sees a voltage from the exhaust gas recirculation (EGR) feedback sensor that is below its normal range. The ECU can no longer tell where the EGR valve is or how much gas is flowing, so it may disable EGR.
P0405 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 60–400 €
- Workshop time
- 0.3–2 h
- Repair difficulty
- Medium
- DIY possible
- Yes
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light on
- Possible rough idle or hesitation
- Higher emissions at technical inspection
Common causes
- Faulty EGR position sensor (often integrated in the EGR valve)
- Signal wire shorted to ground or chafed
- Open 5-volt reference circuit to the sensor
- Faulty differential pressure feedback sensor on systems that use one
Can I keep driving with P0405?
You can keep driving, but have it checked within one to two weeks to avoid poor running and a failed inspection.
What to check first
- Inspect the sensor connector and wiring for damage or corrosion
- Measure the 5-volt reference, ground and signal voltage at the sensor
- Check for a short to ground in the signal wire
- Replace the sensor or EGR valve assembly if wiring checks out
Related codes
- P0404 EGR A control circuit range/performance
- P0406 EGR sensor A circuit high
- P0403 EGR A control circuit/open
- P0402 EGR flow excessive detected
- P0401 Exhaust gas recirculation (EGR) A flow insufficient
- P0400 Exhaust gas recirculation (EGR) A flow malfunction
- P0410 Secondary air injection system A
- P0411 Secondary air injection system incorrect flow detected
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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