Page 1457 of 3051

System DescriptionNLEC1865
Sensor Input Signal to ECMECM func-
tionActuator
Camshaft position sensor Engine speed
Fuel pump
controlFuel pump relay
Ignition switch Ignition signal and start signal
The ECM activates the fuel pump for several seconds after the ignition switch is turned on to improve engine
startability. If the ECM receives a 180É signal from the camshaft position sensor, it knows that the engine is
rotating, and causes the pump to perform. If the 180É signal is not received when the ignition switch is on, the
engine stalls. The ECM stops pump operation and prevents battery discharging, thereby improving safety. The
ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump relay, which in turn controls the
fuel pump.
Condition Fuel pump operation
Ignition switch is turned to ON. Operates for 1 second
Engine running and cranking Operates
When engine is stopped (Signal is not sent from crankshaft position sensor
and camshaft position sensor.)Stops in 1.5 seconds
Except as shown aboveStops
SEF605X
Component DescriptionNLEC1866A turbine type design fuel pump is used in the fuel tank.
CONSULT-II Reference Value in Data Monitor
Mode
NLEC1867
MONITOR ITEM CONDITION SPECIFICATION
FUEL PUMP RLY+Ignition switch is turned to ON (Operates for 1 second)
+Engine running and cranking
+When engine is stopped (stops in 1.5 seconds)ON
+Except as shown above OFF
FUEL PUMPSR20DE
System Description
EC-1032
Page 1458 of 3051
ECM Terminals and Reference Value=NLEC1868Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
21 B/P Fuel pump relay[Ignition switch ªONº]
+For 1 second after turning ignition switch ªONº
[Engine is running]0-1V
[Ignition switch ªONº]
+More than 1 second after turning ignition switch
ªONºBATTERY VOLTAGE
(11 - 14V)
FUEL PUMPSR20DE
ECM Terminals and Reference Value
EC-1033
Page 1459 of 3051
Wiring DiagramNLEC1869MODELS WITH ECM IN ENGINE COMPARTMENTNLEC1869S01
YEC714
FUEL PUMPSR20DE
Wiring Diagram
EC-1034
Page 1460 of 3051
MODELS WITH ECM IN CABINNLEC1869S02
YEC942
FUEL PUMPSR20DE
Wiring Diagram (Cont'd)
EC-1035
Page 1461 of 3051
Diagnostic ProcedureNLEC1870
1 CHECK OVERALL FUNCTION
1. Turn ignition switch ªONº.
2. Pinch fuel feed hose with fingers.
SEF812Z
Fuel pressure pulsation should be felt on the fuel feed hose for 1 second after ignition switch is turned ªONº.
OK or NG
OK©INSPECTION END
NG©GO TO 2.
2 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect fuel pump relay.
SEF633Z
3. Turn ignition switch ªONº.
4. Check voltage between terminals 1, 5 and ground with CONSULT-II or tester.
SEF607X
OK or NG
OK©GO TO 4.
NG©GO TO 3.
FUEL PUMPSR20DE
Diagnostic Procedure
EC-1036
Page 1462 of 3051

3 DETECT MALFUNCTIONING PART
Check the following.
+10A fuse
+15A fuse
+Harness for open or short between fuse and fuel pump relay
©Repair harness or connectors.
4 CHECK POWER GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect fuel level sensor unit and fuel pump harness connector.
SEF632Z
3. Check harness continuity between fuel level sensor unit and fuel pump terminal 3 and body ground, fuel level sensor
unit and fuel pump terminal 5 and fuel pump relay terminal 3.
Refer to wiring diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
+Harness for open or short between fuel level sensor unit and fuel pump and body ground
+Harness for open or short between fuel level sensor unit and fuel pump and fuel pump relay
©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK OUTPUT SIGNAL CIRCUIT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 21 and fuel pump relay connector terminal 2.
Refer to wiring diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 8.
NG©GO TO 7.
FUEL PUMPSR20DE
Diagnostic Procedure (Cont'd)
EC-1037
Page 1463 of 3051

7 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors B2, M15 (LHD models), B47, M65 (RHD models)
+Harness connectors M49, F43 (where fitted)
+Harness connectors M71, F45 (where fitted)
+Harness for open or short between ECM and fuel pump relay
NG©Repair open circuit or short to ground or short to power in harness or connectors.
8 CHECK FUEL PUMP RELAY
Refer to ªComponent Inspectionº, EC-1038.
OK or NG
OK©GO TO 9.
NG©Replace fuel pump relay.
9 CHECK FUEL PUMP
Refer to ªComponent Inspectionº, EC-1038.
OK or NG
OK©GO TO 10.
NG©Replace fuel pump.
10 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-670.
©INSPECTION END
SEF145X
Component InspectionNLEC1871FUEL PUMP RELAYNLEC1871S01Check continuity between terminals 3 and 5.
Conditions Continuity
12V direct current supply between terminals 1 and 2 Yes
No current supply No
If NG, replace relay.
SEF634Z
FUEL PUMPNLEC1871S021. Disconnect fuel level sensor unit and fuel pump harness con-
nector.
2. Check resistance between terminals 3 and 5.
Resistance: 0.2 - 5.0W[at 25ÉC (77ÉF)]
If NG, replace fuel pump.
FUEL PUMPSR20DE
Diagnostic Procedure (Cont'd)
EC-1038
Page 1464 of 3051

SEF903Z
Component DescriptionNLEC1872The power steering oil pressure switch is attached to the power
steering high-pressure tube and detects a power steering load.
When a power steering load is detected, it signals the ECM. The
ECM adjusts the IACV-AAC valve to increase the idle speed and
adjust for the increased load.
CONSULT-II Reference Value in Data Monitor
Mode
NLEC1873Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
PW/ST SIGNAL+Engine: After warming up, idle
the engineSteering wheel in neutral position
(forward direction)OFF
The steering wheel is fully turned ON
ECM Terminals and Reference ValueNLEC1874Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
46 PU/WPower steering oil pressure
switch[Engine is running]
+Steering wheel is fully turnedApproximately 0V
[Engine is running]
+Steering wheel is not turnedApproximately 5V
POWER STEERING OIL PRESSURE SWITCHSR20DE
Component Description
EC-1039