DTC Advanced Diagnostics: P0400
DTC P0400:Exhaust Gas Recirculation (EGR) System Leak Detected

General Description

The exhaust gas recirculation (EGR) system failure conditions include a sticking lift sensor, restricted passages, and leakage from the external piping. At any specific EGR lift value there is a corresponding air/fuel ratio compensation value. If the air/fuel ratio compensation value is greater than the corresponding EGR lift value, the powertrain control module (PCM) detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Once per driving cycle
Sequence
P0404, P2413 are judged as OK
Duration
7.5 seconds or more
DTC Type
Two drive cycles, MIL on

Enable Conditions
Condition
Minimum
Maximum
Engine coolant temperature [ECT SENSOR 1]
156 °F (69 °C)
–
Intake air temperature
[IAT SENSOR (1)]
18 °F (-8 °C)
–
Engine speed
[ENGINE SPEED]
1,500 rpm
4,000 rpm
Vehicle speed
[VEHICLE SPEED]
26 mph (41 km/h)
–
12 volt battery voltage [BATTERY]
10.5 V
–
Fuel feedback
Closed loop at stoichiometric
Monitoring priority
P0133, P0420, P219A
Other
Without excessive load change
[ ]: HDS Parameter

Malfunction Threshold
The air/fuel ratio (A/F) sensor (sensor 1) response parameter according to the opening and closing of the EGR is 26,214 (LT80A) or less.

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
EGR pipe misinstalled
EGR valve failure

Confirmation Procedure
Operating Condition

1.
Start the engine. Hold the engine speed [ENGINE SPEED] at 3,000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on.
2.
Drive the vehicle at a steady speed of 25 mph (40 km/h) or less, for at least 5 minutes.
3.
Drive immediately at a steady speed of 26 mph (41 km/h) or more and engine speed [ENGINE SPEED] between 1,500 - 4,000 rpm for at least 7.5 seconds.
Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
None.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.