P0403

DTC P0403 EGR VOLUME CONTROL VALVE





Description

SYSTEM DESCRIPTION






This system controls flow rate of EGR led from exhaust manifold to intake manifold. The opening of the EGR by-pass passage in the EGR volume control valve changes to control the flow rate. A built-in step motor moves the valve in steps corresponding to the ECM output pulses. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine conditions. The EGR volume control valve remains close under the following conditions.
- Engine stopped
- Engine starting
- Engine idling
- Low engine coolant temperature
- Excessively high engine coolant temperature
- High engine speed
- Wide open throttle
- Low battery voltage






COMPONENT DESCRIPTION

EGR Volume Control Valve
The EGR volume control valve uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECM.






Two windings are turned ON and OFF in sequence. Each time an
ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECM does not issue the pulse signal. A certain voltage signal is issued so that the valve remains at that particular opening.




CONSULT-III Reference Value in Data Monitor Mode
Specification data are reference values.









On Board Diagnosis Logic
This self-diagnosis has the one trip detection logic.









DTC Confirmation Procedure

NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10 V at idle.
1. Start engine and warm it up to normal operating temperature.
2. Rev engine from idle to 2,000 rpm for 10 times.
3. Check DTC.
4. If DTC is detected, go to "Diagnosis Procedure".




Wiring Diagram

EC-EGVC/V-01:

Specification data are reference values and are measured between each terminal and ground.

CAUTION:
Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.









Diagnosis Procedure
1.CHECK EGR VOLUME CONTROL VALVE POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.






2. Disconnect EGR volume control valve harness connector.
3. Turn ignition switch ON.






4. Check voltage between EGR volume control valve terminals 2, 5 and ground with CONSULT-III or tester.

Voltage: Battery voltage


OK or NG
OK - GO TO 3.
NG - GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E5, F14
- Harness for open or short between EGR volume control valve and IPDM E/R
- Repair harness or connectors.
3.CHECK EGR VOLUME CONTROL VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals and EGR volume control valve terminals as follows. Refer to Wiring Diagram.






Continuity should exist.

4. Also check harness for short to ground and short to power.
OK or NG
OK - GO TO 4.
NG - Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK EGR VOLUME CONTROL VALVE
Refer to "Component Inspection".
OK or NG
OK - GO TO 5.
NG - Replace EGR volume control valve.
5.CHECK INTERMITTENT INCIDENT
Refer to Description Diagnosis Procedure.
- INSPECTION END




Component Inspection

EGR VOLUME CONTROL VALVE

With CONSULT-III
1. Turn ignition switch OFF.
2. Disconnect EGR volume control valve harness connector.
3. Check resistance between EGR volume control valve terminal 2 and terminals 1, 3, terminal 5 and terminals 4, 6.

Resistance: 20 - 24 ohms [at 20�C (68F�)]

If NG, replace EGR volume control valve.
If OK, go to next step.
4. Remove EGR volume control valve.
5. Reconnect ECM harness connector and EGR volume control valve harness connector.
6. Turn ignition switch ON.






7. Perform "EGR VOL CONT/V" in "ACTIVE TEST" mode with CONSULT-III.
8. Check that EGR volume control valve shaft moves smoothly forward and backward according to the valve opening steps.






If NG, replace EGR volume control valve.

Without CONSULT-III
1. Turn ignition switch OFF.
2. Disconnect EGR volume control valve harness connector.






3. Check resistance between EGR volume control valve terminal 2 and terminals 1, 3, terminal 5 and terminals 4, 6.

Resistance: 20 - 24 ohms [at 20�C (68F�)]

If NG, replace EGR volume control valve.
If OK, go to next step.
4. Remove EGR volume control valve.
5. Reconnect ECM harness connector and EGR volume control valve harness connector.
6. Turn ignition switch ON and OFF.






7. Check that EGR volume control valve shaft moves smoothly forward and backward according to the ignition switch position.




Removal and Installation

EGR VOLUME CONTROL VALVE
Refer to Service and Repair.