P0402
EGRC-BPT Valve Function:
SYSTEM DESCRIPTION
The EGRC-BPT valve monitors exhaust pressure to activate the diaphragm, controlling throttle body vacuum applied to the EGR valve. In other words, recirculated exhaust gas is controlled in response to positioning of the EGR valve or to engine operation.
ON BOARD DIAGNOSIS LOGIC
If too much EGR flow exists due to an EGRC-BPT valve malfunction, off idle engine roughness will increase.
If the roughness is excessive, then the vacuum to the EGR valve is interrupted through the EGRC-solenoid valve. If the engine roughness is reduced at that time, the EGRC-BPT valve malfunction is indicated.
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
CAUTION: Always drive vehicle at a safe speed.
NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.
TESTING CONDITION:
- For best results, perform the test at temperature above 5 °C (41 °F) or higher.
- Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.
With Consult
1. Install vacuum gauge between EGRC-BPT valve and EGR valve as shown in the figure.
2. Start engine and warm it up to normal operating temperature.
3. Stop engine and wait at least 5 seconds.
4. Turn ignition switch "ON" and select "EGRC-BPT/V P0402" of "EGR SYSTEM" in "DTC WORK SUPPORT" mode with CONSULT-II.
5. Start engine (TCS switch "OFF") and let it idle.
6. Touch "START".
7. Check the output voltage of "THRTL POS SEN" at closed throttle position and open throttle position.
8. When the following conditions are met, "TESTING" will be displayed on the CONSULT-II screen and the bar chart may increase. Maintain the conditions many times until "COMPLETED" appears.
Selector lever: Suitable position
CMPS-RPM (POS): 1,000 - 1,600 rpm
Vehicle speed: 30 - 56 km/h (19 - 35 MPH)
B/FUEL SCHDL: 2.0 - 3.2 msec
THRTL POS SEN: X - (X + 0.89) V
X = Voltage value measured at step 7
- The bar chart on CONSULT-II screen indicates the status of this test. However, the test may be finished before the bar chart becomes full scale.
- If the bar chart indication does not continue to progress, completely release accelerator pedal once and try to meet the conditions again.
- If "TESTING" does not appear on CONSULT-II screen, retry from step 4.
If NG, go to "DIAGNOSTIC PROCEDURE".
If OK, go to next step.
9. Open engine hood.
10. Raise engine speed to 2,000 to 2,800 rpm under no-load and hold it. Then touch "NEXT" of the CONSULT-II screen.
11. Check vacuum gauge while keeping engine speed 2,000 to 2,800 rpm.
Vacuum should be 0 to -20.0 kPa (0 to -150 mmHg, 0 to -5.91 inHg).
If NG, go to "DIAGNOSTIC PROCEDURE".
If OK, touch "YES" in the CONSULT-II screen.
12. Check the rubber tube between intake manifold collector, EGR valve and EGRC-BPT valve for misconnection, cracks, blockages or twisting.
If NG, repair.
If OK, touch "YES" in the CONSULT-II screen.
13. If CONSULT-II instructs to carry out "OVERALL FUNCTION CHECK", go to next step. If "NG" is displayed, refer to "DIAGNOSTIC PROCEDURE".
OR
OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the EGRC-BPT valve. During the check, a 1st trip DTC might not be confirmed.
1. Install vacuum gauge between EGRC-BPT valve and EGR valve as shown in the figure.
2. Lift up vehicle.
3. Connect the intake manifold collector and the EGRC-BPT valve with a rubber tube that has 0.5 mm (0.020 in) dia. orifice. (The intake manifold vacuum will be directly applied to the EGRC-BPT valve.)
4. Start engine and shift to 1st position.
5. Check vacuum gauge while keeping engine speed 2,400 ± 400 rpm.
Vacuum should be 0 to -20.0 kPa (0 to - 150 mmHg, 0 to -5.91 inHg).
If NG, go to "DIAGNOSTIC PROCEDURE".
If OK, go to next step.
6. Check rubber tube between the intake manifold collector, EGRC-solenoid valve and EGRC-BPT valve for misconnection, cracks, blockages or twisting.
7. If NG, repair or replace.
DIAGNOSTIC PROCEDURE
COMPONENT INSPECTION
EGRC-BPT valve
1. Plug one of two ports of EGRC-BPT valve.
2. Vacuum from the other port and check leakage without applying any pressure from under EGRC-BPT valve.
Leakage should exist.