200SX SE L4-1597cc 1.6L DOHC MFI (GA16DE) (1997)
EGR Backpressure Transducer: Description and Operation
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 roughness is large, then vacuum
to the EGR valve is interrupted through the EGR valve & EGRC-solenoid valve. If the engine roughness is reduced at that time, the EGRC-BPT
valve malfunction is indicated.