Honda ACCORD HYBRID 2005 Service Manual page 275

PGM-FI System
The p r o g r a m m e d fuel injection (PGM-FI) system is a
sequential multiport fuel injection system.
Air Conditioning (A/C) Compressor Clutch Relay
W h e n the PCM receives a d e m a n d for cooling f r o m the
A/C s y s t e m , it delays the compressor f r o m being
energized, and enriches the m i x t u r e to assure s m o o t h
transition to the A/C mode.
Air Fuel Ratio (A/F) Sensor
The A/F sensor operates over a w i d e air/fuel range. The
A/F sensor is installed upstream of the WU-TWC, and
sends signals to the PCM w h i c h varies the duration of
fuel injection accordingly.
Barometric Pressure (BARO) Sensor
The BARO sensor is inside the PCM. It converts
atmospheric pressure into a voltage signal that
modifies the basic duration of the fuel injection
discharge.
Camshaft Position (CMP) Sensor
The CMP sensor input is used by the PCM to determine
ignition t i m i n g at start up (cranking) and w h e n crank
angle is a b n o r m a l .
TERMINAL
MAGNET
Crankshaft Position (CKP) Sensor
The CKP sensor detects crankshaft speed and is used by
the PCM to determine ignition t i m i n g and t i m i n g for
fuel injection of each cylinder as w e l l as detecting
engine misfire.
CKP CKP
SENSOR A SENSOR B
CKP SENSOR SUBHARNESS
Engine Coolant Temperature (ECT) Sensor 1/2
The ECT sensor 1/2 is a temperature dependent resistor
(thermistor). The resistance of the thermistor decreases
as the engine coolant temperature increases.
THERMISTOR
Ignition Timing Control
The PCM contains the m e m o r y for basic ignition t i m i n g
at various engine speeds and m a n i f o l d absolute
pressures. It also adjusts the t i m i n g according to engine
coolant temperature.
Injector Timing and Duration
The PCM contains the m e m o r y for basic discharge
duration at various engine speeds and m a n i f o l d
pressures. The basic discharge duration, after being
read out f r o m the m e m o r y , is further m o d i f i e d by
signals sent f r o m various sensors to obtain the final
discharge duration.
By m o n i t o r i n g long t e r m fuel t r i m , the PCM detects long
t e r m malfunctions in the fuel system and sets a
diagnostic trouble code (DTC).
(cont'd)
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