P0402

DTC P0402 Exhaust Gas Recirculation (EGR) Flow Excessive

Circuit Description

The ECM controls the EGR valve opening based on the engine running condition and by controlling the EGR solenoid.

The EGR valve position is detected by the position sensor and relayed to the ECM. When the proper enabling conditions are met the ECM monitors EGR gas flow amount while monitoring the mass air flow (MAF) signal. An expected MAF amount should be detected while engine running. If the ECM detects the MAF amount is less than expected this DTC will set.

Condition for Running the DTC

^ DTCs P0027 P0079 P0080 P0101 P0102 P0103 P0112 P0113 P0116 P0117 P0118 P0201 - P0204 P0261 P0264 P0267 P0270 P02E2 P02E3 P02E7 P02E8 P02E9 P0300 P0301 - P0304 P0335 P0336 P0403 P0404 P0405 P0406 P0500 P0506 P0507 P0602 P0642 P0643 P0652 P0653 P1125 P2002 P2146 - P2151 P1293 P2227 P2228 P2229 P2454 P2455 and P268A are not set.
^ The battery voltage is between 10 to 16 volts.
^ The ignition switch is ON.
^ The engine speed is between 550 to 750 RPM and does not vary more than 30 RPM.
^ The vehicle is stationary.
^ The accelerator pedal is not depressed.
^ The barometric pressure is more than 11 psi (75 kPa).
^ The intake air temperature is more than 19°F (-7°C).
^ The engine coolant temperature is between 149 to 198°F (65 to 92°C).
^ The EGR control is commanded ON.
^ The intake airflow valve position is less than 50%.
^ The turbocharger control is under normal condition.
^ The exhaust brake valve is commanded OFF.
^ The DPF regeneration is not running.

Condition for Setting the DTC

^ The ECM detects that the MAF amount is less than the calculated range during idle. This indicates excessive amount of EGR flow.

Action Taken When the DTC Sets

^ The ECM illuminates the MIL on the second consecutive driving cycle when the diagnostic runs and fails. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type B.

Condition for Clearing the DTC

^ Refer to DTC Type Definitions for Condition for Clearing the MIL/DTC - Type B.

Diagnostic Aids

^ If an intermittent condition is suspected refer to Intermittent Conditions in this section.
^ A sticking or intermittently sticking the EGR valve may set this DTC.

Circuit/System Testing DTC P0402