Code No. P0403: Exhaust Gas Recirculation Control System <Vehicles for Hong kong>

OPERATION

Power is supplied to the EGR valve (terminal No. 2 and No. 5) from the engine control relay (terminal No. 1).

The engine-A/T-ECU (terminal No. 3, No. 12, No. 19 and No. 26) makes the power transistor in the unit be in "ON", and that makes currents go on the EGR valve (terminal No. 1, No. 3, No. 4 and No. 6).

FUNCTION

Based on the signal from engine-A/T-ECU, the EGR valve (stepper motor) controls the EGR rate.

TROUBLE JUDGMENT

Check Condition

Battery positive voltage is 10.3 V or higher.

Judgment Criterion

The EGR valve motor coil surge voltage (battery positive voltage +2 V) is not detected for 3 seconds.

PROBABLE CAUSE

Failed EGR valve

Open/short circuit in EGR valve circuit or loose connector contact

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-116 EGR valve connector

Q: Is the check result normal?

YES: Go to Step 2

.
NO: Repair.

STEP 2. Check EGR valve itself.

Check EGR control solenoid valve itself [Refer to GROUP 17 - Emission Control System - Exhaust Gas Recirculation (EGR) System - EGR Valve (stepper motor) Check <4G69>.

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Replace EGR valve (stepper motor).

STEP 3. Perform voltage measurement at B-116 EGR valve connector.

Disconnect connector, and measure at harness side.

Ignition switch: ON

Voltage between terminal No. 2, No. 5 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Go to Step 4

STEP 4. Connector check: B-17X engine control relay connector

Q: Is the check result normal?

YES:

Check and repair harness between B-116 (terminal No. 2, No. 5) EGR valve connector and B-17X (terminal No. 1) engine control relay connector.

Check power supply line for open/short circuit.

NO: Repair.

STEP 5. Perform voltage measurement at C-134 engine-A/T-ECU connector.

Disconnect connector, and measure at harness side.

Ignition switch: ON

Voltage between terminal No. 3, No. 12, No. 19, No. 26 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Go to Step 6

STEP 6. Connector check: C-134 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between B-116 EGR valve connector and C-134 engine-A/T-ECU connector

Check harness between B-116 (terminal No. 1) EGR valve connector and C-134 (terminal No. 3) engine-A/T-ECU connector

Check harness between B-116 (terminal No. 3) EGR valve connector and C-134 (terminal No. 12) engine-A/T-ECU connector

Check harness between B-116 (terminal No. 4) EGR valve connector and C-134 (terminal No. 19) engine-A/T-ECU connector

Check harness between B-116 (terminal No. 6) EGR valve connector and C-134 (terminal No. 26) engine-A/T-ECU connector

Check power supply line for open/short circuit.

NO: Repair.

STEP 7. Connector check: C-134 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Repair.

STEP 8. Check harness between B-116 EGR valve connector and C-134 engine-A/T-ECU connector.

Check harness between B-116 (terminal No. 1) EGR valve connector and C-134 (terminal No. 3) engine-A/T-ECU connector

Check harness between B-116 (terminal No. 3) EGR valve connector and C-134 (terminal No. 12) engine-A/T-ECU connector

Check harness between B-116 (terminal No. 4) EGR valve connector and C-134 (terminal No. 19) engine-A/T-ECU connector

Check harness between B-116 (terminal No. 6) EGR valve connector and C-134 (terminal No. 26) engine-A/T-ECU connector

Check output line for damage.

Q: Is the check result normal?

YES: Go to Step 9

.
NO: Repair.

STEP 9. Check harness between B-116 (terminal No. 2, No. 5) EGR valve connector and B-17X (terminal No. 1) engine control relay connector.

Check power supply line for damage.

Q: Is the check result normal?

YES: Replace engine-A/T-ECU.
NO: Repair.


Code No. P0403: Exhaust Gas Recirculation Control System <Vehicles for Hong kong>

OPERATION Power is supplied to the EGR valve (terminal No. 2 and No. 5) from the engine control relay (terminal No. 1). The engine-A/T-ECU (terminal No. 3, No. 12, No. 19 and No. 26) makes the power transistor in the unit be in "ON", and that makes currents go on the EGR valve (terminal No. 1, No. 3, No. 4 and No. 6).
FUNCTION Based on the signal from engine-A/T-ECU, the EGR valve (stepper motor) controls the EGR rate.
TROUBLE JUDGMENT Check Condition Battery positive voltage is 10.3 V or higher. Judgment Criterion The EGR valve motor coil surge voltage (battery positive voltage +2 V) is not detected for 3 seconds.
PROBABLE CAUSE Failed EGR valve Open/short circuit in EGR valve circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. Connector check: B-116 EGR valve connector
	Q: Is the check result normal? YES: Go to Step 2 . NO: Repair.
	STEP 2. Check EGR valve itself. Check EGR control solenoid valve itself [Refer to GROUP 17 - Emission Control System - Exhaust Gas Recirculation (EGR) System - EGR Valve (stepper motor) Check <4G69>. Q: Is the check result normal? YES: Go to Step 3 . NO: Replace EGR valve (stepper motor).
	STEP 3. Perform voltage measurement at B-116 EGR valve connector.
	Disconnect connector, and measure at harness side. Ignition switch: ON Voltage between terminal No. 2, No. 5 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 5 . NO: Go to Step 4 .
	STEP 4. Connector check: B-17X engine control relay connector
	Q: Is the check result normal? YES: Check and repair harness between B-116 (terminal No. 2, No. 5) EGR valve connector and B-17X (terminal No. 1) engine control relay connector. Check power supply line for open/short circuit. NO: Repair.
	STEP 5. Perform voltage measurement at C-134 engine-A/T-ECU connector.
	Disconnect connector, and measure at harness side. Ignition switch: ON Voltage between terminal No. 3, No. 12, No. 19, No. 26 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 7 . NO: Go to Step 6 .
	STEP 6. Connector check: C-134 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between B-116 EGR valve connector and C-134 engine-A/T-ECU connector Check harness between B-116 (terminal No. 1) EGR valve connector and C-134 (terminal No. 3) engine-A/T-ECU connector Check harness between B-116 (terminal No. 3) EGR valve connector and C-134 (terminal No. 12) engine-A/T-ECU connector Check harness between B-116 (terminal No. 4) EGR valve connector and C-134 (terminal No. 19) engine-A/T-ECU connector Check harness between B-116 (terminal No. 6) EGR valve connector and C-134 (terminal No. 26) engine-A/T-ECU connector Check power supply line for open/short circuit. NO: Repair.
	STEP 7. Connector check: C-134 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 8 . NO: Repair.
	STEP 8. Check harness between B-116 EGR valve connector and C-134 engine-A/T-ECU connector.
	Check harness between B-116 (terminal No. 1) EGR valve connector and C-134 (terminal No. 3) engine-A/T-ECU connector Check harness between B-116 (terminal No. 3) EGR valve connector and C-134 (terminal No. 12) engine-A/T-ECU connector Check harness between B-116 (terminal No. 4) EGR valve connector and C-134 (terminal No. 19) engine-A/T-ECU connector Check harness between B-116 (terminal No. 6) EGR valve connector and C-134 (terminal No. 26) engine-A/T-ECU connector Check output line for damage. Q: Is the check result normal? YES: Go to Step 9 . NO: Repair.
	STEP 9. Check harness between B-116 (terminal No. 2, No. 5) EGR valve connector and B-17X (terminal No. 1) engine control relay connector.
	Check power supply line for damage. Q: Is the check result normal? YES: Replace engine-A/T-ECU. NO: Repair.