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1F2 -- 42 M161 ENGINE CONTROLS
D AEW OO M Y_2000
FUEL PUMP
YAA1F380
Requirements for Fuel Pump
ItemSpecified ValueItemSpecified Value
System Pressure3.8 barMinimum Delivery at 8V30 Litre/Hr
Maximum Pressure8.5 bar (12 V)Operating Voltage8V
Minimum Pressure5.0 bar (12 V)Maximum Allowable
Current7.5 A
Nominal Voltage12 VAmbient Temperature-- 30 ~ +70°C
Minimum Amount
of Fuel Supply114 Liter/Hr (12 V, 3.8 bar,
-- 30 ~ +70°C)Maximum Amount
of Fuel Supply165 Liter/Hr (12V, 3.8 bar,
-- 3 0 ~ + 7 0°C)
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M161 ENGINE CONTROLS 1F2 -- 43
D AEW OO M Y_2000
KAB1F210
Failure
CodeDescriptionTrouble AreaMaintenance Hint
34Fuel pump relay short
circuit to batteryWhen short circuit to power
sourceDInspection the Engine Control Module
(ECM) pin 33 about short circuit or
openwithbadcontact
35Fuel pump relay short
circuit to ground or openWhen short circuit to ground
or open
openwithbadcontact
DInspection the fuel pump relay
DInspection the ECM
Circuit Description
When the ignition switch is turned ON, the ECM will activate the pump relay and run the in -- tank fuel pump. The fuel
pump willoperate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.
If there are no reference pulses, the ECM will shut off the fuel pump within 2 seconds after the ignition switch is turned
ON, engine stopped or engine stalled.
Fuel Pump Relay Inspection
Measure the voltage between the ECM terminal No. 33 and Ground.
Ignition Switch : ON
0v(for1~2sec.)
Cranking0v
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1F2 -- 44 M161 ENGINE CONTROLS
D AEW OO M Y_2000
Measure the Fuel Delivery from the Fuel Pump
1. Disconnect the return pipe from fuel distributor and insert the appropriate hose into it.
2. Place the hose end into the beaker with the minimum capacity of 1 Liter
3. Turn the ignition switch to “ON” position.
4. Connect the terminal No. 33 and No. 5 of ECM with a service wire.
5. Measure the fuel delivery from the fuel pump
Specified Value
1 Liter/max. 35 sec.
Notice:Check the fuel filter and fuel line when the fuel delivery is not within specified value.
Measure the Current Consumption of Fuel Pump
1. Remove the fuel pump relay from fuse and relay box in trunk, and turn the ignition switch to “ON” position.
2. Using a multimeter, measure the current consumption by connecting the terminal No. 30 and No. 87 of the fuel
pump relay connector.
Specified Value
5~9A
Notice:Replace the fuel pump relay if the measured value is over 9 A.
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M161 ENGINE CONTROLS 1F2 -- 53
D AEW OO M Y_2000
Fuel Pressure Test
Tools Required
103 589 00 21 00 Fuel Pressure Gauge
1. Turn the ignition switch to “OFF” position.
2. Remove the fuel pressure test connector.
YAA1F700
3. Connect the fuel pressure gauge to the fuel pressure test connector.
4. Test the fuel pressure at idling by operating the engine using the fuel pressure gauge 103 589 00 21 00.
Vacuum Hose Connected (bar)
3.2~3.6
Vacuum Hose Disconnected (bar)3.7~4.2
5. Replace the pressure regulator diaphragm if out of the specification.
Internal Leakage Test
1. Connect the fuel pressure gauge 103 589 00 21 00 to
the fuel pressure test connector.
YAA1F0K0
2. Stop the engine for approximately 30 minutes and then check the fuel pressure changes.
Pressure change
Fuel pressure drops slowlyDFuel leakage at the injector
DFaulty fuel pressure regulator ’s diaphragm and O-ring
Fuel pressure drops rapidlyDFaulty check valve in the fuel pump
3. If there is no change in fuel pressure and maintain the following pressure over 30minutes, it is normal.
Fuel pressure (bar)
≥2.5
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M161 ENGINE CONTROLS 1F2 -- 55
D AEW OO M Y_2000
The pressure difference between the fuel pressure and
the intake manifold is about 3.8 bars during the full load.
YAA1F500
1. Fuel Pressure Regulator
2. Intake Manifold
3. Fuel Return (to fuel tank)
4. Fuel Supply (from fuel pump)
5. Fuel Pressure (approx. 3.8 bars)
6. Intake Manifold Negative Pressure (0 bar)
The spring chamber (9) is connected to the intake man-
ifold with the vacuum hose at the intake pipe connection
(7). The negative pressure generated in the intake man-
ifold activates the diaphragm, and thus the fuel pressure
gets reduced to the rate of the operating extent of the
diaphragm by the intake manifold’s negative pressure.
YAA1F510
Consequently, the fuel pressure in the fuel distributor
changes by the intake manifold’s negative pressure, and
the injector ’s fuel pressure gets reduced independentlyto the throttle valve’s position. Thus, the fuel injection
volume can only be determined according to the injec-
tor’s injecting duration.
The pressure difference between the fuel pressure and
the intake manifold is approx. 3.2 bars during idling.
YAA1F520
1. Fuel Pressure Regulator
2. Intake Manifold
3. Fuel Return (to fuel tank)
4. Fuel Supply (from fuel pump)
7. Fuel Pressure (approx. 3.2 bars)
8. Intake Manifold Negative Pressure (0.6 bars)
YAA1F530
A. Fuel pressure
B. Intake Manifold Negative Pressure
LL. Idling
TL. Partial load
VL. Full load
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1F2 -- 86 M161 ENGINE CONTROLS
D AEW OO M Y_2000
ENGINE CONTROL MODULE
YAA1F830
The Engine Control Module (ECM), located inside the right side kick panel, is the control center of the fuel injection
system. It constantly looks at the information from various sensors and controls the systems that affect the vehicle’s
performance. Engine rpm and air mass are used to measure the air intake quantity resulting in fuel injection metering.
The ECM also performs the diagnostic functions of the system. It can recognize operational problems, store failure
code(s) which identify the problem areas to aid the technician in making repairs.
There are no serviceable parts in the ECM. The calibrations are stored in the ECM in the Programmable Read Only
Memory (PROM).
The ECM supplies either 5 or 12 volts to power the sensors or switches. This is done through resistance in the ECM
which are so high in value that a test light will not come ON when connected to the circuit. In some cases, even an
ordinary shop voltmeter will not give and accurate reading because its resistance is too low. You must use a digital
voltmeter with a 10 Mohm input impedance to get accurate voltage readings. The ECM controls output circuits such as
the ignition coils, the fuel injectors, the fuel pump relay, the camshaft actuator, the canister purge valve, etc., by con-
trolling the ground circuit.
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M161 ENGINE CONTROLS 1F2 -- 95
D AEW OO M Y_2000
MAINTENANCE AND REPAIR
YAA1F700
ON VEHICLE SERVICE
DISCHARGING THE PRESSURE IN
FUEL SYSTEM
Removal and Installation Procedure
1. Remove the fuel pressure test connector.
Installation Notice
Tightening Torque
25 NSm (18 lb-ft)
YAA1F710
2. Remove the fuel pressure in fuel system by pressing
the service valve with a clean, pointy tool.
Notice:Place a cloth so that the fuel doesn’t stain
around.
3. Installation should follow the removal procedure in
the reverse order.
YAA1F170
FUEL PUMP
Tools Required
661 589 00 46 00 Fuel Tank Cap Wrench
Removal and Installation Procedure
Caution: The fuel system is under pressure. To
avoid fuel spillage and the risk of personal injury or
fire, it is necessary to relieve the fuel system pres -
sure before disconnecting the fuel lines.
1. Relieve the fuel system pressure. Refer to “Discharg-
ing the Pressure in Fuel System” in this section.
2. Disconnect the negative battery cable.
3. Put aside the floor carpet to remove the fuel pump ac-
cess cover.
4. Remove the fuel pump access cover.
5. Remove the fuel pump wiring connectors.
6. Disconnect the fuel supply and return pipes.
7. Remove the fuel pump locking cap band.
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YAA1F550
8. Using the fuel tank cap wrench 661 589 00 46 00,
remove the locking cap.
9. Remove the pump from the fuel tank.
Notice:Check the condition of the seal and replace if
necessary. Drain the fuel before removing the pump.
10. Perform an operational check of the fuel pump.
11. Installation should follow the removal procedure in
the reverse order.
YAA1F190
FUEL FILTER
Removal and Installation Procedure
1. Disconnect the negative battery cable.
Caution: The fuel system is under pressure. To
avoid fuel spillage and the risk of personal injury or
fire, it is necessary to relieve the fuel system pres -
sure before disconnecting the fuel lines.
2. Relieve the fuel system pressure. Refer to “Dis-
charging the Pressure in Fuel System” in this sec-
tion.
3. Disconnect the fuel lines from the fuel filter.
Installation Notice
Tightening Torque
28 NSm (21 lb-ft)
4. Remove the fuel filter mounting bracket bolt .
Installation Notice
Tightening Torque
6NSm (53 lb-in)
Notice:Place the fuel pump pad. There may be a corro-
sion due to the contact between the fuel filter and the
bracket.
5. Remove the fuel filter.
6. Install the fuel filter.
7. Perform a leak test of the fuel filter.
8. Installation should follow the removal procedure in
the reverse order.