Code No. P0400: Exhaust Gas Recirculation (EGR) System <SOHC>

function

The operation of the exhaust gas recirculation system changes the intake pipe pressure.

The engine-A/T-ECU operates the exhaust gas recirculation system during the decelerated operation, and checks the intake pipe pressure that may change.

TROUBLE JUDGMENT

Check Condition

Engine coolant temperature approximately 80°C or more.

Engine speed 1,000 - 2,000 r/min.

Intake air temperature 5°C or more.

Atmospheric pressure 76 kPa or more.

Vehicle speed 32 km/h or more.

Fuel cut mode

Volumetric efficiency 20% or less.

Judgment Criterion

Placing the exhaust gas recirculation control solenoid valve in the "ON" position changes the pressure of the intake system by 3 kPa or more.

PROBABLE CAUSE

Failed exhaust gas recirculation valve

Low exhaust gas recirculation control negative pressure

Failed exhaust gas recirculation control solenoid valve

Failed vacuum hose

Failed manifold absolute pressure sensor

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-II/III diagnosis code

Q: Is any other diagnosis code than P0400 output?

YES: Inspection chart for diagnosis code (Refer to

).
NO: Go to Step 2

STEP 2. MUT-II/III data list

Refer to Data list reference table .

Item 32: Manifold absolute pressure sensor

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Check manifold absolute pressure (MAP) sensor system (Refer to Inspection Procedure No. 32

STEP 3. Check EGR vacuum hose for leakage and clogging.

Q: Is the check result normal?

YES: Go to Step 4

.
NO: Replace EGR vacuum hose.

STEP 4. Check EGR control solenoid valve itself.

Check EGR control solenoid valve itself [Refer to GROUP 17 - Emission Control System - Exhaust Gas Recirculation (EGR) System ].

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Replace EGR control solenoid valve.

STEP 5. Check EGR valve itself.

Check exhaust gas recirculation valve itself [Refer to GROUP 17 - Emission Control System - Exhaust Gas Recirculation (EGR) System ].

Q: Is the check result normal?

YES: Replace engine-A/T-ECU.
NO: Replace EGR valve.


Code No. P0400: Exhaust Gas Recirculation (EGR) System <SOHC>

function The operation of the exhaust gas recirculation system changes the intake pipe pressure. The engine-A/T-ECU operates the exhaust gas recirculation system during the decelerated operation, and checks the intake pipe pressure that may change.
TROUBLE JUDGMENT Check Condition Engine coolant temperature approximately 80°C or more. Engine speed 1,000 - 2,000 r/min. Intake air temperature 5°C or more. Atmospheric pressure 76 kPa or more. Vehicle speed 32 km/h or more. Fuel cut mode Volumetric efficiency 20% or less. Judgment Criterion Placing the exhaust gas recirculation control solenoid valve in the "ON" position changes the pressure of the intake system by 3 kPa or more.
PROBABLE CAUSE Failed exhaust gas recirculation valve Low exhaust gas recirculation control negative pressure Failed exhaust gas recirculation control solenoid valve Failed vacuum hose Failed manifold absolute pressure sensor Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. MUT-II/III diagnosis code Q: Is any other diagnosis code than P0400 output? YES: Inspection chart for diagnosis code (Refer to ). NO: Go to Step 2 .
	STEP 2. MUT-II/III data list Refer to Data list reference table . Item 32: Manifold absolute pressure sensor Q: Is the check result normal? YES: Go to Step 3 . NO: Check manifold absolute pressure (MAP) sensor system (Refer to Inspection Procedure No. 32 ).
	STEP 3. Check EGR vacuum hose for leakage and clogging. Q: Is the check result normal? YES: Go to Step 4 . NO: Replace EGR vacuum hose.
	STEP 4. Check EGR control solenoid valve itself. Check EGR control solenoid valve itself [Refer to GROUP 17 - Emission Control System - Exhaust Gas Recirculation (EGR) System ]. Q: Is the check result normal? YES: Go to Step 5 . NO: Replace EGR control solenoid valve.
	STEP 5. Check EGR valve itself. Check exhaust gas recirculation valve itself [Refer to GROUP 17 - Emission Control System - Exhaust Gas Recirculation (EGR) System ]. Q: Is the check result normal? YES: Replace engine-A/T-ECU. NO: Replace EGR valve.