Honda Ridgeline. Manual - part 68
０７
０８
Idle Control System
Fuel Supply System
Catalytic Converter System
Brake Pedal Position Switch
Power Steering Pressure (PSP) Switch
Fuel Cutoff Control
Fuel Pump Control
PGM-FI Main Relay 1 and 2
Warm Up/Three Way Catalytic Converter (WU-TWC)
and Under-Floor Three Way Catalytic Converter (TWC)
WU-TWC
TWC
11-36
Fuel and Emissions Systems
System Description (cont’d)
HOUSING
WARM UP
THREE WAY
CATALYST
FRONT
(Bank 2)
WARM UP THREE WAY
CATALYST REAR
(Bank 1)
FRONT OF
VEHICLE
FRONT OF
VEHICLE
UNDER-FLOOR
THREE WAY
CATALYST
HOUSING
When the engine is cold, the A/C compressor is on, the
transmission is in gear, the brake pedal is pressed, the
power steering load is high, or the alternator is
charging, the PCM sends signals to the throttle actuator
to maintain the correct idle speed.
The brake pedal position switch signals the PCM when
the brake pedal is pressed.
The PSP switch signals the PCM when the power
steering load is high.
During deceleration with the throttle valve closed,
current to the injectors is cut off to improve fuel
economy at engine speeds over 950 rpm. Fuel cutoff
control also occurs when the engine speed exceeds
6,500 rpm, regardless of the position of the throttle
valve, to protect the engine from over-revving. When
the vehicle is stopped, the PCM cuts the fuel at engine
speeds over 5,000 rpm. Engine speed of fuel cut is
lower on a cold engine.
When the ignition is turned on, the PCM grounds
PGM-FI main relay 2 (FUEL PUMP) which feeds current
to the fuel pump for 2 seconds to pressurize the fuel
system. With the engine running, the PCM grounds
PGM-FI main relay 2 (FUEL PUMP) and feeds current to
the fuel pump. When the engine is not running and the
ignition is on, the PCM cuts ground to PGM-FI main
relay 2 (FUEL PUMP) which cuts current to the fuel
pump.
PGM-FI main relay 1 (FI MAIN) is energized whenever
the ignition switch is ON (II) to supply battery voltage to
the PCM, power to the injectors, and power for PGM-FI
main relay 2 (FUEL PUMP). PGM-FI main relay 2 (FUEL
PUMP) is energized to supply power to the fuel pump
for 2 seconds when the ignition switch is turned ON (II),
and when the engine is cranking or running.
The WU-TWC/TWC converts hydrocarbons (HC), carbon
monoxide (CO), and oxides of nitrogen (NOx) in the
exhaust gas to carbon dioxide (CO ), nitrogen (N ), and
water vapor.
2
2