DTC P0400

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

General Description 

Courtesy of HONDA, U.S.A., INC.

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	11 seconds or more
DTC Type	Two drive cycles, MIL on

Enable Conditions 

Condition		Minimum	Maximum
Engine coolant temperature [ECT SENSOR 1]		156 deg. F (69 deg. C)	-
Intake air temperature[IAT SENSOR (2)]		27 deg. F (-3.0 deg. C)	-
Engine speed[ENGINE SPEED]		1, 600 rpm	4, 000 rpm
MAP value [MAP SENSOR]	2, 000 rpm	38 kPa (11.1 inHg, 280 mmHg)	83 kPa (24.5 inHg, 620 mmHg)
	3, 000 rpm	40 kPa (11.9 inHg, 300 mmHg)	74 kPa (21.7 inHg, 550 mmHg)
Vehicle speed[VEHICLE SPEED]		26 mph (41 km/h)	-
12 volt battery voltage [BATTERY]		10.5 V	-
Fuel trim		0.69	1.47
Fuel feedback		Closed loop at stoichiometric
Monitoring priority		P0133, P0420, P219A
Other		Without excessive load change

Malfunction Threshold 

The air/fuel ratio (A/F) sensor (sensor 1) response parameter according to the opening and closing of the EGR is 36, 045 (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 

Courtesy of HONDA, U.S.A., INC.

• 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.
• Drive the vehicle at a steady speed of 25 mph (40 km/h) or less, for at least 5 minutes.
• Drive immediately at a steady speed of 26 mph (41 km/h) or more and engine speed [ENGINE SPEED] between 1, 600 - 4, 000 rpm for at least 11 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.