P0401moderate severityPowertrain
EGR Flow Insufficient Detected
on 2001 Volvo S80 4.4L V8 · AWD
What this code means
The EGR system is not flowing enough exhaust gas. This is one of the most common EGR codes.
Symptoms
- Check Engine Light
- Pinging under load
- Failed emissions (high NOx)
- Slight rough idle
Common causes
- Clogged EGR passages (most common)
- EGR valve stuck closed
- Clogged EGR tube
- Faulty DPFE/MAP sensor
- Carbon buildup in intake manifold
Diagnostic steps
- Check EGR passages for carbon restriction
- Test EGR valve by applying vacuum (should open and idle should change)
- Inspect EGR tube between exhaust and valve
- Test DPFE sensor (Ford) or EGR position sensor
- Clean carbon from intake ports
Repair notes
Clean EGR passages and valve. This is maintenance, not just a repair. Replace EGR valve if cleaning fails.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1