Upstream And Downstream Solenoids - Jeep 1987 Wrangler Workshop Manual

ENGINES
FUEL FEEDBACK SYSTEMS
Upstream and Downstream Solenoids
The upstream and downstream solenoids
(Pulse Air System) distribute air to the exhaust
pipe and catalytic converter.
The upstream ( A ) and downstream ( B )
solenoids are located on a bracket attached to
the top of the cylinder head cover.
The idle solenoid is also located on the same
bracket.
The upstream and downstream solenoids are
energized by the MCU. The MCU energizes the
upstream solenoid to route air into the exhaust
pipe at a location after the oxygen sensor.
When energized by the MCU, the downstream
solenoid routes air into the second bed of the
dual-bed catalytic converter (TWC-COC).
B-260