The EGR (Exhaust Gas Recirculation) system is used to divert some of the exhaust gas to the engine inlet system in order to reduce an excess of air and the temperature in the combustion chamber. This device also significantly reduces emissions of the nitrous oxides at the exhaust. The EGR system compromise a solenoid valve, a proportional pneumatic valve and an air flow meter. The EGR solenoid valve controls the opening and closing the pneumatic valve using the low pressure from the braking assistance circuit. The low pressure is created by the vaccum pump located at the end of the alternator. The duty control of the solenoid valve is determined by the injection computer depending on the air flow requested. In case of EGR solenoid valve failure, the engine performance will be reduced.
If an unusually low or high airflow rate is being read by the EGR system, or there are airflow readings that do not correspond to the expected engine load (too high or too low) during two driving cycles, these codes will be set and the MIL will be turned on. If the EGR electrical circuit is short to ground or open circuit during two driving cycles, this code will be set and the MIL will be turned on.
DTC NO.
Detecting Condition
Possible Cause
P 0401
P 0402
P 0405
P 0406
? P 0401
Error is recognized if |actual intaked air volume - target intaked air volume| is below 200 mg/stroke at the condition of the engine rpm from 750 to 2000 and fuel injection quantity below 15 mcc
? P 0402
Error is recognized if |actual intaked air volume - target intaked air volume| is above 320 mg/stroke at the condition of the engine rpm from 750 to 2000 and fuel injection quantity below 15 mcc
? P 0405
Open circuit :
? Short circuit to ground
? Wire broken
? Too high temperature in power stage
? P 0406
Short circuit to battery line
?Engine Condition : RUN
? Fuel Limit : YES (P0401/P0402)
? Fuel Cut : NO
? EGR OFF : YES
? MIL : YES
? Open or short in circuit
? EGR sol. valve
? AFS
? ECM