P0402

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 large, 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.

DTC Confirmation Procedure

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch OFF and wait at least 5 seconds before conducting the next test.

TESTING CONDITION:
- Always perform at a temperature above 5 °C (41 °F).
- Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

With CONSULT-II




1. Install vacuum gauge between EGRC-BPT valve and EGR valve as shown in the illustration.
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 and let it idle.
6. Touch "START".
7. Check the output voltage of "THRTL POS SEN" (at closed throttle position) and note it.













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.

NOTE:
- 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 2.

9. If CONSULT-II instructs to carry out "Overall Function Check", go to next step. If "NG" is displayed, refer to "Diagnostic Procedure" below.
10. Open engine hood.




11. Raise engine speed to 2,400 to 3,200 rpm under no-load and hold it. Then touch "NEXT" on CONSULT-II screen.




12. Check vacuum gauge while keeping engine speed at 2,400 to 3,200 rpm.

Vacuum should be 0 to -20 kPa (0 to -150 mmHg, 0 to -5.91 in Hg).

If NG, go to "Diagnostic Procedure" below.
If OK, touch "YES" on the CONSULT-II screen.
13. Check the EGR valve lifting when rewing from 2,000 rpm to 4,000 rpm quickly under no load.
EGR valve should lift up, and go down without sticking when the engine is returned to idle.
If NG, check EGR valve.
If OK, touch "YES" or the CONSULT-II screen.
14. Check the rubber tube between intake manifold collector, EGRC-solenoid valve, EGR valve and EGRC-BPT valve for cracks, blockages or twisting.
If NG, repair or replace.
If OK, touch "YES" on the CONSULT-II screen.

Overall Function Check
Use this procedure to check the overall function of the EGRC-BPT valve. During this check, a 1st trip DTC might not be confirmed.

Without CONSULT-II




1. Install vacuum gauge between EGRC-BPT valve and EGR valve as shown in the illustration.
2. Lift up vehicle.
3. Start engine and shift to 1st gear position.
4. Check vacuum gauge while keeping engine speed at 2,400 to 3,200 rpm.

Vacuum should be 0 to -20 kPa (0 to 150 mmHg, 0 to 5.91 in Hg).

If NG, go to "Diagnostic Procedure" below. If OK, go to next step.
5. Check the EGR valve lifting when rewing from 2,000 rpm to 4,000 rpm quickly under no load.
EGR valve should lift up, and go down without sticking when the engine is returned to idle.
6. Check rubber tube between intake manifold collector, EGRC solenoid valve, EGR valve and EGRC-BPT valve for misconnection, cracks or blockages.
7. If NG, go to "Diagnostic Procedure" below.

Diagnostic Procedure

Step 1 - 4:

Step 5:

Step 6:

Step 7:

Step 8 - 9: