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DTC P0400-00: Exhaust gas recirculation (EGR) system insufficient flow
 
 
 
 
TECHNICAL DESCRIPTION
  • When the EGR valve (stepper motor) is actuated from the fully closed position toward the open position while the engine is running, EGR gas flows.
  • The ECM checks how the EGR gas flow signal changes.
 
 
DESCRIPTIONS OF MONITOR METHODS
Small manifold pressure change during EGR operation from closed to open.
 
 
MONITOR EXECUTION
Continuous.
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
  • Exhaust gas recirculation (EGR) stepper motor monitor
Sensor (The sensor below is determined to be normal)
  • Mass airflow sensor
  • Engine coolant temperature sensor
  • Intake air temperature sensor
  • Barometric pressure sensor
  • Manifold absolute pressure sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • Engine coolant temperature is higher than 76°C (169°F).
  • Volumetric efficiency is lower than 40 percent.
  • Barometric pressure is more than 76 kPa (22.4 in.Hg).
  • Intake air temperature is higher than –1°C (30°F).
  • More than 10 seconds have passed since the engine starting sequence was completed.
  • At least 20 seconds have passed since the last monitor was complete.
  • 12V battery positive voltage is higher than 10.3 volts.
  • PHEV requested torque is between 71 and 79 N·m.
  • More than 1.5 second has elapsed after the above mentioned conditions have been met.
  • Vehicle speed is higher than 30 km/h (19 mph).
  • Engine speed is between 1,156 and 1,656 r/min.
Judgment Criterion
  • When the EGR valve opens to the prescribed opening, the intake manifold pressure fluctuation width is less than 2.0 kPa (0.59 in.Hg).
  • The condition is met for 3 times continuously in the same driving cycle.
 
 
FAIL-SAFE AND BACKUP FUNCTION
None.
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 5 OBD- II DRIVE CYCLE.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Manifold absolute pressure sensor failed.
  • Contaminated EGR valve, EGR cooler and EGR passage.
  • ECM failed.
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
1.STEP 1. Using scan tool (M.U.T.-III SE), check the data list.
Use scan tool (M.U.T.-III SE) to check the data list (Refer to DATA LIST REFERENCE TABLE).
  • Item number 70: Boost Sensor
Q: Is the check result normal?
Perform troubleshooting for the manifold absolute pressure sensor circuit (Refer to DTC P0107-00: Manifold Absolute Pressure Sensor circuit low input DTC P0107-00: Manifold Absolute Pressure Sensor circuit low input, and Refer to DTC P0108-00: Manifold Absolute Pressure Sensor circuit high input DTC P0108-00: Manifold Absolute Pressure Sensor circuit high input).
 
2.STEP 2. Check EGR valve itself.
Check EGR valve itself [Refer to ENGINE, Engine, Motor and Emission Control – Emission Control, Exhaust Gas Recirculation (EGR) System EXHAUST GAS RECIRCULATION (EGR) VALVE (STEPPER MOTOR) CHECK].
Q: Is the check result normal?
Replace the EGR valve [Refer to ENGINE, Engine, Motor and Emission Control – Emission Control, Exhaust Gas Recirculation (EGR) System EXHAUST GAS RECIRCULATION (EGR) VALVE REMOVAL AND INSTALLATION].
 
3.STEP 3. Check for exhaust leaks from the EGR valve, EGR cooler, EGR pipe and EGR intake pipe.
Q: Are the check result normal?
Repair it.
 
4.STEP 4. Check the EGR valve contamination, the EGR cooler contamination, the EGR pipe contamination and the EGR intake pipe contamination.
Q: Are the EGR valve, the EGR cooler, the EGR pipe and the EGR intake pipe clogged?
Repair the EGR valve, the EGR cooler, the EGR pipe and the EGR intake pipe contamination.
 
5.STEP 5. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 5 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P0400-00 set?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION).
Intermittent malfunction (Refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points – How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).