EGR VOL CON/V CIR

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
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 REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.




ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values, and are measured between each terminal and (25) (ECM ground).




FAIL-SAFE MODE
When the ECM enters the fail-safe mode, the MIL illuminates.




ON BOARD DIAGNOSIS LOGIC




DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.

TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is more than 10 V at idle.

With Consult
1. Turn ignition switch "ON" and select "DATA MONITOR" mode with CONSULT.
2. Start engine and warm it up to normal operating temperature.
3. Rev engine from idle to 2,000 rpm 10 times.
4. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".

OR

With Generic Scan Tools
1. Start engine and warm it up to normal operating temperature.
2. Rev engine from idle to 2,000 rpm 10 times.
3. Select "MODE 3" with GST.
4. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".

OR

Without Scan Tools
1. Start engine and warm it up to normal operating temperature.
2. Rev engine from idle to 2,000 rpm 10 times.
3. Turn ignition switch "OFF", wait at least 10 seconds and then turn "ON".
4. Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.
5. If 1st trip DTC is detected, go to "DIAGNOSTIC PROCEDURE".







WIRING DIAGRAM




DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION







With Consult
1. Disconnect EGR volume control valve harness connector.
2. Check resistance between the following terminals.
terminal (2) and terminals (1),(3)
terminal (5) and terminals (4),(6)
Resistance: 20.9 - 23.1 Ohm [At 20 °C (68 °F)]
3. Reconnect EGR volume control valve harness connector.
4. Remove air duct.
5. Remove EGR volume control valve from intake manifold collector.
(The EGR volume control valve harness connector should remain connected.)
6. Turn ignition switch "ON".
7. Perform "EGR VOL CONT/V" in "ACTIVE TEST" mode with CONSULT. Check that EGR volume control valve shaft moves smoothly forward and backward according to the valve opening.
If NG, replace the EGR volume control valve.

OR







Without Consult
1. Disconnect EGR volume control valve harness connector.
2. Check resistance between the following terminals.
terminal (2) and terminals (1),(3)
terminal (5) and terminals (4),(6)
Resistance: 20.9 - 23.1 Ohm [At 20 °C (68 °F)]
3. Turn ignition switch "ON" and "OFF". Check that EGR volume control valve shaft moves smoothly forward and backward according to the ignition switch position.
If NG, replace the EGR volume control valve.