DTC 0306

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.

DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

CAUTION:
- Always perform the test at a location of -10°C (14°F) or higher.
- Always drive vehicle at a safe speed.
- 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.










With Consult
1) Start engine and warm it up to normal operating temperature.
2) Stop engine and wait at least 5 seconds.
3) Turn ignition switch "ON" and select "EGRC-BPT/V P0402" of "EGR SYSTEM" in "DTC WORK SUPPORT" mode with CONSULT.
4) Start engine and let it idle.
5) Touch "START".
6) Check the output voltage of "THRTL POS SEN" (at closed throttle position) and note it.
7) When the following conditions are met, "TESTING" will be displayed on the CONSULT screen and the bar chart may increase. Maintain the conditions many times until "COMPLETED" appears.
Selector lever: Suitable position
CMPS-RPM (REF): 1,200 - 1,600 rpm (A/T)
1,280 - 1,440 rpm (M/T)
Vehicle speed: 30 - 54 km/h (19 - 34 MPH) (A/T)
30 - 100 km/h (19 - 62 MPH) (M/T)
B/FUEL SCHDL: 2.2 - 2.3 ms (A/T)
1.9 - 2.1 ms (M/T)
THRTL POS SEN: (X + 0.04) - (X + 0.30) V (A/T)
(X + 0.09) - (X + 0.30) V (M/T)
X = Voltage value measured at step 6)
- The bar chart on CONSULT 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 screen, retry from step 2).
8) If "OK" is displayed, carry out "OVERALL FUNCTION CHECK" below. If "NG" is displayed, refer to "DIAGNOSTIC PROCEDURE".




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
1) Disconnect the rubber tube to intake manifold collector at the EGRC-solenoid valve.
2) Disconnect the rubber tube to the EGRC-solenoid valve at the EGRC-BPT valve. Connect the intake manifold collector and the EGRC-BPT valve directly 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.)
3) Start engine.
4) Check for the EGR valve lifting with engine at idle speed under no load.
EGR valve should remain closed.
5) Check the EGR valve lifting when revving from 1,500 rpm up to 3,000 rpm 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 EGRC-solenoid valve and throttle body for misconnection, cracks or blockages.




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 EGR-BPT valve.
Leakage should exist.