1996 TOYOTA T100 fuel pump

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ON
Fuel Return Hose
P25086
DI−10
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
7 Check fuel pressure.
PREPARATION:
(a) Be sure that enough fuel is in the tank.
(b) Connect the TOYOTA hand−held tester to the DLC3.
(c) Turn the ignition switch ON and push the TOYOTA hand−
held tester main switch ON.
(d) Use ”ACTIVE TEST” mode to operate the fuel pump.
CHECK:
Check for fuel pressure in the fuel return hose when it is pinched
off.
HINT:
At this time, you will hear a fuel flowing noise.
NG Proceed to page MF−1 and continue to trouble-
shoot.
OK
8 Check for spark.
PREPARATION:
(a) Disconnect the high−tension cord from the spark plug.
(b) Remove the spark plug.
(c) Install the spark plug to the high−tension cord.
(d) Disconnect the injector connector.
(e) Ground the spark plug.
CHECK:
Check if the spark occurs while engine is being cranked.
NOTICE:
To prevent excess fuel being injected from the injectors
during this test, don’t crank the engine for more than 5 ∼ 10
seconds at a time.
NG Proceed to page IG−1 and continue to trouble-
shoot.
OK
Proceed to problem symptoms table on page
DI−21.

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− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
(b) TOYOTA Enhanced Signals.
TOYOTA hand−held tester displayMeasurement ItemNormal Condition*
MISFIRE RPMEngine RPM for first misfire rangeMisfire 0: 0 rpm
MISFIRE LOADEngine load for first misfire rangeMisfire 0: 0 g/r
INJECTORFuel injection time for cylinder No.1Idling: 2.5 − 4.3 ms
IAC DUTY RATIOIntake Air Control Valve Duty Ratio
Opening ratio rotary solenoid type IAC valveIdling: 24.8 − 50.0 %
STARTER SIGStarter SignalCranking: ON
CTP SWClosed Throttle Position Switch SignalThrottle Fully Closed: ON
A/C SIGA/C Switch SignalA/C ON: ON
STOP LIGHT SWStop Light Switch SignalStop light switch ON: ON
FC IDLFuel Cut Idle: Fuel cut when throttle valve fully
closed, during decelerationFuel cut operating: ON
FC TAUFuel Cut TAU: Fuel cut during very light loadFuel cut operating: ON
CYL #1, CYL #2, CYL #3, CYL #4Abnormal revolution variation for each cylinder0 %
IGNITIONTotal number of ignition for every 1,000
revolutions0 − 2,000
EGRT GASEGR Gas Temp. Sensor ValueEGR not operating: Temp. between intake air
temp. and engine coolant temp.
EGR SYSTEMEGR System Operating ConditionIdling: OFF
A/C CUT SIGA/C Cut SignalA/C S/W OFF: ON
FUEL PUMPFuel Pump SignalIdling: ON
EVAP (PURGE) VSVEVAP VSV SignalIdling: OFF
TOTAL FT B1Total Fuel Trim Bank 1: Average value for fuel
trim system of bank 1Idling: 0.8 − 1.2 V
O2 LR B1, S1
Oxygen Sensor Lean Rich Bank 1, Sensor 1 Re-
sponse time for oxygen sensor output to switch
from lean to rich
Idling after warming up: 0 − 1,000 msec.
O2 RL B1, S1
Oxygen Sensor Rich Lean Bank 1, Sensor 1 Re-
sponse time for oxygen sensor output to switch
from rich to lean
Idling after warming up: 0 − 1,000 msec.
*: If no conditions are specifically stated for ”ldling”, it means the shift lever is at N or P position, the A/C switch
is OFF and all accessory switches are OFF.

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− DIAGNOSTICSENGINE (3RZ−FE)
DI−21
1996 TOYOTA T100 (RM449U)
PROBLEM SYMPTOMS TABLE
SymptomSuspect AreaSee page
Engine does not crank (Does not start)1. Starter and starter relayST−15
No initial combustion (Does not start)1. ECM power source circuit
2. Fuel pump control circuitDI−11 5
DI−11 8
No complete combustion (Does not start)1. Fuel pump control circuitDI−11 8
Engine cranks normally (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit
3. CompressionDI−11 0
DI−11 8
EM−3
Cold engine (Difficult to start)1. Starter signal circuit
2. Fuel pump control circuitDI−11 0
DI−11 8
Hot engine (Difficult to start)1. Starter signal circuit
2. Fuel pump control circuitDI−11 0
DI−11 8
High engine idle speed (Poor idling)1. A/C signal circuit (Compressor circuit)
2. ECM power source circuitAC−79
DI−11 5
Low engine idle speed (Poor idling)1. A/C signal circuit (Compressor circuit)
2. Fuel pump control circuitAC−79
DI−11 8
Rough idling (Poor idling)1. Compression
2. Fuel pump control circuitEM−3
DI−11 8
Hunting (Poor idling)1. ECM power source circuit
2. Fuel pump control circuitDI−11 5
DI−11 8
Hesitation/Poor acceleration (Poor driveability)1. Fuel pump control circuit
2. A/T faultyDI−11 8
DI−282
Surging (Poor driveability)1. Fuel pump control circuitDI−11 8
Soon after starting (Engine stall)1. Fuel pump control circuitDI−11 8
During A/C operation (Engine stall)1. A/C signal circuit (Compressor circuit)
2. Engine control module (ECM)AC−79
IN−26

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− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
2 Check for heated oxygen sensor (bank 1 sensor 1 ) data.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(b) Warm up the engine to normal operating temp.
CHECK:
Read heated oxygen sensor output voltage and short−term fuel trim.
RESULT:
PatternHeated oxygen sensor output voltageShort−term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about + 20 %
2Rich condition (Changes at 0.4 V or more)Changes at about − 20 %
3Except 1 and 2
3 Check for heated oxygen sensor (bank 1 sensor
1) (See page MF−49).
1, 2
3 Check fuel pressure (See page MF−5).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page MF−10).
OK
4 Check injector injection (See page MF−16).
NG Replace injector.
OK

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P23816
P23817
A00066
For M/T
#10 (+) #20 (+)
#10 (+) #20 (+)
For A/T
− DIAGNOSTICSENGINE (3RZ−FE)
DI−61
1996 TOYOTA T100 (RM449U)
2 Check voltage of ECM terminal for injector of failed cylinder.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between applicable terminal of ECM connec-
tor and body ground.
OK:
Voltage: 9 − 14 V
OK Go to step 4.
NG
3 Check resistance of injector of misfiring cylinder (See page MF−16).
NG Replace injector.
OK
Check for open and short in harness and con-
nector between injector and ECM (See page
IN−26).
4 Check fuel pressure (See page MF−5).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page MF−10).
OK

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EFI Relay
EFI
AM2
AM1
ALT
BatteryIG Switch
IG
STIGN
Park/Neutral
Position Switch
(A/T)
Starter
Relay
Clutch
Start
Switch
(M/T)
StarterCircuit Opening Relay
L2
L1Fuel Pump
ECM
FC
Tr
STA
NE (STA Signal)
(NE Signal) From
Crankshaft
Position
Sensor DI−11 8
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
Fuel Pump Control Circuit
CIRCUIT DESCRIPTION
In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition switch to
the starter relay coil, the starter relay switches on and current flows to coil L1 of the circuit opening relay.
Thus the circuit opening relay switches on, power is supplied to the fuel pump and the fuel pump operates.
When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to coil L2 of the circuit
opening relay, the relay witches on and the fuel pump operates.
While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the
fuel pump also keeps operating.
DI0U8−03

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ECM
EFI
AM2
AM1 ALT
BatterySwitch
Park/
Switch
StarterRelay
Clutch
Start
Switch
E01 FC 14 14
E4 E7
(M/T)(A/T) G−Y 16
IE1 G−Y L
1
4
6 Circuit
Opening
BJ1
8
L
W−BW−BBJ1
11
W−BIC IC
2 W−R W−R
W−B
EA19
EA
3
B−WB−W
B−WIE1
21 Starter
Relay
IC
(M/T)
B−W 1
5
23
1
2
B−RW−B
W−B (A/T)
W
B B−W
3
2
2
2 Relay EFI 22
5
1
2 2 2 22 R/B No.2
2
2
2
W
W B−Y
W−R
W
14
8
IA3
IA3
W−R
W
8
EA1
IG
67
1A
1C3
17
IGN
J/B
No.2
B−Y
B−Y (A/T)
(M/T) B
IE1
415
B
5
6
B−YIE1
22Neutral
Position
(A/T)
Fuel
Pump
− DIAGNOSTICSENGINE (3RZ−FE)
DI−11 9
1996 TOYOTA T100 (RM449U)
WIRING DIAGRAM

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ON
Fuel Return Hose
DI−120
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
TOYOTA hand−held tester:
1 Connect TOYOTA hand−held tester and check operation of fuel pump.
PREPARATION:
(a) Connect the TOYOTA hand−held tester to the DLC3.
(b) Turn the ignition switch ON and push the TOYOTA hand−
held tester main switch ON.
(c) Use ”ACTIVE TEST” mode to operate the fuel pump.
CHECK:
Check for fuel pressure in the fuel return hose when it is pinched
off.
OK:
There is pressure in the fuel return hose.
HINT:
At this time, you will hear a fuel flowing noise.
OK Go to step 7.
NG
2 Check for ECM power source circuit (See page DI−11 5).
NG Repair or replace.
OK