P0400 OBD Trouble Code

Exhaust Gas Recirculation "A" Flow

EGR System Fault Conditions

Engine runtime over 3 minutes, ECT sensor input over 170°F, engine speed from 1952-2400 rpm in closed loop, MAP input from 1.80-2.70v, TP sensor from 0.6-1.8v, VSS over 3 mph, then with EGR Monitor Test activated, the PCM detected that the amount of EGR gas flow change was too small with the EGR solenoid switched off to on. Refer to Monitor Test, code repair chart to test EGR valve control vacuum circuits and the MDP sensor.

EGR Flow Fault Conditions

Engine running in steady state driving conditions (closed loop), then the PCM detected insufficient EGR flow

EGR System Performance Conditions

DTC P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0601, P0718 and P0724 not set, ECT input above 81°F, engine speed 500-900 rpm, BARO input above 95 kPa, MAP input below 24 kPa, IAC counts steady, no A/C Clutch, Brake switch or TCC transitions, VSS input above 14 mph, then during these Decel Mode Test conditions (throttle angle below 1%, not in DFCO, EGR duty cycle at 0%, then with the EGR solenoid enabled), the PCM detected that the change in the MAP sensor input was less than a predetermined amount stored in memory

Exhaust gas recirculation (EGR) system - flow excessively high or low

Wiring, hose leak/blockage, EGR valve, EGR/EVAP valve, ECM