P0404

Exhaust gas recirculation (EGR) circuit range/performance malfunction

Detection Conditions

• The ECU monitors the EGR solenoid (vacuum) valve's accumulated on-time when monitoring conditions are met.  If the accumulated on-time exceeds threshold while activating the EGR system, the ECU determines that there is a performance problem with EGR solenoid valve (vent) circuit.

Diagnostic Support Notes

• This is a continuous monitor (CCM)
• Check engine indicator illuminates if the ECU detects the above malfunction condition in two consecutive drive cycles
• PENDING CODE is available
• FREEZE FRAME DATA is available
• DTC is stored in ECU memory

Possible Causes

• EGR valve malfunction
• EGR solenoid valve (vacuum) malfunction
• EGR solenoid valve (vent) malfunction
• Vacuum hoses disconnected, misrouted, or damaged
• Related wiring harness malfunction
• ECU malfunction

[P0404 - From 2002 Mazda Millenia factory service manual]