P0405
PPowertrainEGR Sensor A Circuit Low
What does this code mean?
Severity : MediumP0405 indicates low voltage in the exhaust gas recirculation (EGR) sensor A circuit. This sensor tells the engine control module the position or flow of the EGR valve. With a signal that is too low, the module can no longer control recirculation properly.
Symptoms
- Check engine light on.
- Loss of power or limp mode on some engines.
- Unstable idle.
- Higher NOx emissions.
Possible causes
- Faulty EGR position sensor, often built into the valve.
- Wiring shorted to ground or open.
- Corroded or damaged connector.
- Missing 5 V reference supply.
- Engine control module fault, which is rare.
Diagnosis and repair
- Inspect the EGR valve connector and wiring.
- Measure reference voltage, ground and signal with a multimeter.
- Compare actual and commanded position in live data.
- Clean or replace the EGR valve or its sensor if the reading is wrong.
- Clear the code and road test.
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Code
P0405
Category
Powertrain
Prefix
P
Standard
OBD-II / SAE J2012