hi, you can tell me what kind of car, and I can suggestion your the tool to repair it.
Trouble code P0401 means: Exhaust Gas Recirculation Malfunction Replace the EGR Valve
Replace EGR module...do it yourself....takes about 25 minutes
Remove EGR valve and inspect for blocked or restricted passages.
po401 mean Exhaust Gas Recirculation Flow Insufficient Detected.
p0401 is related to EGR valve flow. Possible bad EGR, check passageway under EGR to see if its plugged See also for the DPFE before changing the EGR Valve.
simple buy a new car with no alarm like this...problem solve :P
Insufficient EGR (exhaust gas recirculation) valve. Suggest you replace the valve.
P0401 = Insufficient EGR Flow
replace the EGR valve and reset the OBD II Exhaust Gas Recirculation valve
Trouble code P0401 means:Exhaust gas recirculation flow insufficient detected
Trouble code P0401 means: Exhaust Gas Recirculation Malfunction
P0401 = Insufficient EGR Flow