P0401 Exhaust Gas Recirculation Flow Insufficient Detected
Check Conditions
At least 20 seconds have passed since the last monitor was complete. Engine coolant temperature is higher than 76°C (169°F). Engine speed is at between 910 and 1,650 r/min. Intake air temperature is higher than 0°C (32°F). Barometric pressure is higher than 76 kPa (11 psi). Vehicle speed is 30 km/h (18.7 mph) or more. At least 90 seconds have passed since manifold differential pressure sensor output voltage fluctuated 1.5 volts or more. The throttle valve is closed. Volumetric efficiency is lower than 28 percent. The PCM monitors for this condition for 3 cycles of 2 seconds each during the drive cycle.
Judgement Criteria
When the EGR valve opens to the prescribed opening, when intake manifold pressure fluctuation width is lower than 2.6 kPa (0.37 psi).
- Dirtiness of the EGR valve and EGR passage.
- EGR valve (stopper motor) failed.
- Open or shorted EGR valve (stopper motor) circuit, or loose connector.
- Manifold differential pressure sensor failed.
- PCM failed.
Check Conditions
At least 20 seconds have passed since the last monitor was complete. Engine coolant temperature is higher than 76°C (169°F). Engine speed is at between 910 and 1,650 r/min. Intake air temperature is higher than 0°C (32°F). Barometric pressure is higher than 76 kPa (11 psi). Vehicle speed is 30 km/h (18.7 mph) or more. At least 90 seconds have passed since manifold differential pressure sensor output voltage fluctuated 1.5 volts or more. The throttle valve is closed. Volumetric efficiency is lower than 28 percent. The PCM monitors for this condition for 3 cycles of 2 seconds each during the drive cycle.
Judgement Criteria
When the EGR valve opens to the prescribed opening, when intake manifold pressure fluctuation width is lower than 2.6 kPa (0.37 psi).
- Dirtiness of the EGR valve and EGR passage.
- EGR valve (stopper motor) failed.
- Open or shorted EGR valve (stopper motor) circuit, or loose connector.
- Manifold differential pressure sensor failed.
- PCM failed.