P0401 Mazda - Exhaust Gas Recirculation Flow Insufficient Detected
- EGR passage clogged
- Faulty EGR Vacuum Modulator Valve
- Faulty EGR Valve
- Faulty EGR solenoid valve
- EGR solenoid valve harness is open or shorted
- EGR solenoid valve circuit poor electrical connection
- Dead (Weak) battery
- Faulty EGR temperature sensor and circuit
- Exhaust gas leaks
EGR flow malfunction could be caused by a clogged EGR valve or EGR tube. Before replacing any parts try cleaning the EGR valve, tube and passages.
When is the code detected?
- Low EGR flow control is detected
- Engine Light ON (or Service Engine Soon Warning Light)
- Possible engine hesitation
P0401 Mazda Description
Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.
MAZDA Technical Service Bulletins for P0401 code
2007 MAZDA B-SERIES TRUCK Engine And Engine Cooling:engine Details
2007 MAZDA B-SERIES TRUCK 061000 Engine And Engine Cooling:engine Details
2001 MAZDA TRIBUTE Engine And Engine Cooling:engine Details
2002 MAZDA TRIBUTE Engine And Engine Cooling:engine Details
2001 MAZDA B4000 Engine And Engine Cooling:engine Details
2002 MAZDA B4000 Engine And Engine Cooling:engine Details
2001 MAZDA TRIBUTE Electrical System Details
2002 MAZDA TRIBUTE Electrical System Details
2001 MAZDA B4000 Electrical System Details
2002 MAZDA B4000 Electrical System Details
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