Page 650 of 1449
MPI -Troubleshooting13A-118
Standard Wave Pattern
Observation condition
FunctionSpecial patterns
Pattern heightLow
Pattern selectorDisplay
Engine r/minIdle speed
Standard Wave Pattern
Crank angle
sensor output
wave pattern(V)
75_BTDC2 engine revolutions
(1 camshaft revolution)
5_BTDCThe time (cycle time) T is
reduced when the engine
speed increases
0
Camshaft position
sensor output
wave pattern
TDC: Top dead centre131_49_
No. 1 TDC No. 3 TDC No. 4 TDC No. 2 TDCTime
056_34_
Wave Pattern Observation Points
Check that cycle time T becomes shorter when the engine speed increases.
Examples of Abnormal Wave Patterns
DExample 1
Cause of problem
Sensor interface malfunction
Wave pattern characteristics
Rectangular wave pattern is output even when the engine
is not started.
Page 651 of 1449

MPI -Troubleshooting13A-119
DExample 2
Cause of problem
Loose timing belt
Abnormality in sensor disk
Wave pattern characteristics
Wave pattern is displaced to the left or right.
INJECTOR
Measurement Method
1. Disconnect the injector connector, and then connect the
special tool (test harness: MB991348) in between.
(All terminals should be connected.)
2. Connect the analyzer special patterns pickup to terminal
No. 2 of the injector connector.
Alternate Method (Test harness not available)
1. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 1. (When checking the No. 1
cylinder.)
2. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 14. (When checking the No.
2 cylinder.)
3. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 2. (When checking the No. 3
cylinder.)
4. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 15. (When checking the No.
4 cylinder.)
Standard Wave Pattern
Observation conditions
FunctionSpecial patterns
Pattern heightVariable
Variable knobAdjust while viewing the wave pattern
Pattern selectorDisplay
Engine r/minIdle speed
Special
patterns
pickupAnalyzer
Page 655 of 1449

MPI -Troubleshooting13A-123
IGNITION COIL AND POWER TRANSISTOR
DIgnition coil primary signal
Refer to GROUP 16 - Ignition system.
DPower transistor control signal
Measurement Method
1. Disconnect the ignition coil connector, and connect the
special tool (test harness: MB991658) in between. (All
terminals should be connected.)
2. Connect the analyzer special patterns pickup to terminal
No. 3 of each ignition coil connector in turn.
Alternate Method (Test harness not available)
1. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 10 (No. 1 - No. 4), terminal
No. 23 (No. 2 - No. 3) respectively.
Standard Wave Pattern
Observation condition
FunctionSpecial patterns
Pattern heightLow
Pattern selectorDisplay
Engine r/minApproximately 1,200 r/min
Standard wave pattern
Crank angle
sensor output
wave pattern
Power transistor
control signal
wave pattern(V)
75_BTDC5_BTDCT: Revolution time corresponding to a crank angle of 180_
Compression top dead center
θ: Spark
advance
angleIgnition period
OFF ON
Dwell section
T1: Time computed by the engine-ECUTime θ T1T
6
4
2
0
4
2
0
Special
patterns
pickupAnalyzer
Page 658 of 1449

MPI -On-vehicle Service13A-126
THROTTLE BODY (THROTTLE VALVE AREA)
CLEANING
1. Remove the air intake hose from the throttle body.
2. Spray cleaning fluid on a clean cloth.
3. Wipe off the dirt around the throttle valve with the cloth
sprayed with cleaning fluid.
Caution
(1) Do not spray the cleaning fluid directly to the
throttle valve.
(2) Make sure the cleaning fluid does not enter the
motor from the bypass line. Also make sure it
does not enter the sensor through the shaft.
(3) Be careful not to rub off the molybden applied
around the throttle valve shaft.
4. Attach the air intake hose.
5. Adjust the basic idle speed. (Refer to P.13A-127.)
THROTTLE POSITION SENSOR ADJUSTMENT
1. Connect the MUT-IIto the diagnosis connector.
When not using the MUT-II, proceed as follows:
(1) Disconnect the throttle position sensor connector, and
connect the special tool (test harness: MB991536)
between the disconnected connector taking care not
to confuse the terminal to be connected.
(2) Connect digital voltmeter between the terminal No.
2 and the terminal No. 4 of the throttle position sensor
connector.
2. Turn the ignition switch to “ON” position (but do not start
the engine).
3. Check the output voltage of the throttle position sensor.
Standard value: 535 - 735 mV
Throttle valve molybdenum
application section15 mm
15 mm
Equipment side connectorThrottle
position
sensor
Throttle
body
MB991536
Throttle position sensor
Page 659 of 1449

MPI -On-vehicle Service13A-127
4. If not within the standard value, loosen the throttle position
sensor mounting bolts. Then rotate the sensor body to
adjust.
5. Turn the ignition switch to “LOCK” (OFF) position.
6. Remove the MUT-II. If the MUT-IIis not used, remove
the special tool, and then connect the throttle position
sensor connector.
7. If a diagnosis code is displayed, erase the diagnosis code
by using the MUT-IIor disconnect the negative battery
cable from the battery terminal and then leave it for at
least ten seconds. After that, reconnect the battery cable,
and then let the engine run at idle for approximately 10
minutes.
BASIC IDLE SPEED ADJUSTMENT
NOTE
(1) The basic idling speed has been adjusted by the
speed adjusting screw by the manufacturer, and there
should usually be no need for readjustment.
(2) If the adjustment has been changed by mistake, the
idle speed may become too high or the idle speed
may drop too low when loads from components such
as the A/C are placed on the engine. If this occurs,
adjust by the following procedure.
(3) The adjustment, if made, should be made after first
confirming that the spark plugs, the injectors, the idle
speed control servo, the compression pressure, etc.,
are all normal.
1. Before inspection and adjustment, set the vehicle to the
pre-inspection condition.
2. Connect the MUT-IIto the diagnosis connector (16-pin).
NOTE
When the MUT-IIis connected, the diagnosis control
terminal should be earthed.
3. Start the engine and run at idle.
4. Select the item No. 30 of the MUT-IIActuator test.
NOTE
This holds the idle speed control servo at the basic step
to adjust the basic idle speed.
5. Check the basic idle speed.
Standard value: 850±100 r/min
NOTE
(1) The engine speed may be 20 to 100 r/min lower
than indicated above for a new vehicle [driven
approximately 500 km or less], but no adjustment
is necessary.
(2) If the engine stalls or the engine speed is low even
though the vehicle has been driven approximately
500 km or more, it is probable that deposits are
adhered to the throttle valve, so clean it. (Refer to
P.13A-126.)
Page 663 of 1449
MPI -On-vehicle Service13A-131
COMPONENT LOCATION
NameSymbolNameSymbol
A/C relayJFuel pump relay 1, 2Q
A/C switchTFuel pump relay 3H
Air flow sensor (integrated intake air tempera-
ture sensor and barometric pressure sensor)OFuel pump resistorH
Camshaft position sensorNIdle speed control servo (stepper motor)G
Crank angle sensorKIgnition coil (integrated power transister)M
Detonation sensorEInjectorC
Diagnosis connectorSOxygen sensor (front)L
EGR control solenoid valveDOxygen sensor (rear)X
Engine control relayIPower steering fluid pressure switchA
Engine coolant temperature sensorNResistor (for injector)H
Engine warning lamp (check engine lamp)RSecondary air control solenoid valveD
Engine-ECUUThrottle position sensorG
Fan motor relayJVehicle speed sensorF
Fuel pressure control solenoid valveBWaste gate solenoid valveP
ABCDEFGHIJK
LMNOP
QRSTU
Page 664 of 1449

MPI -On-vehicle Service13A-132
ENGINE CONTROL RELAY CONTINUITY CHECK
Tester
connection
terminalBattery voltageNormal state
2-3Not energizedContinuity
1-4Not energizedNo continuity
Energized [Connect terminal No. 2
to battery (+) terminal, and connect
terminal No. 3 to battery ( - )
terminal.]Continuity
FUEL PUMP RELAY 1, 2 CONTINUITY CHECK
Tester
connection
terminalBattery voltageNormal state
1-4Not energizedContinuity
2-3Not energizedNo continuity
Energized [Connect terminal No. 1
to battery (+) terminal, and connect
terminal No. 4 to battery ( - )
terminal.]Continuity
FUEL PUMP RELAY 3 CONTINUITY CHECK
Tester
connection
terminalBattery voltageNormal state
3-4Not energizedContinuity
1-2Not energizedContinuity
Energized [Connect terminal No. 2
to battery (+) terminal, and connect
terminal No. 1 to battery ( - )
terminal.]No continuity
FUEL PUMP RESISTOR CHECK
1. Disconnect the fuel pump resistor connector.
2. Measure the resistance between the terminals.
Standard value: 0.45 - 0.65Ω
3. If the value is deviated from the standard value, replace
the fuel pump resistor.
INTAKE AIR TEMPERATURE SENSOR CHECK
1. Disconnect the air flow sensor connector.
2. Measure resistance between terminal No. 5 and terminal
No. 6.
Standard value:
13 - 17 kΩ(at - 20_C)
5.7 - 6.7 kΩ(at 0_C)
2.3 - 3.0 kΩ(at 20_C)
1.0 - 1.5 kΩ(at 40_C)
0.56 - 0.76 kΩ(at 60_C)
0.30 - 0.42 kΩ(at 80_C)
Equipment
side connectorEngine control
relay
1
32
4
Equipment
side connector Fuel pump
relay 1
Fuel pump
relay 21
32
4
Equipment
side connector
Fuel pump
relay 3 1
32
4
Equipment
side connector
Fuel pump
resistor 12
Air flow sensor
Equipment side connector
123456 7
Page 665 of 1449

MPI -On-vehicle Service13A-133
3. Measure resistance while heating the sensor using a hair
drier.
Normal condition:
Temperature (_C)Resistance (kΩ)
HigherSmaller
4. If the value deviates from the standard value or the
resistance remains unchanged, replace the air flow sensor
assembly.
ENGINE COOLANT TEMPERATURE SENSOR
CHECK
Caution
Be careful not to touch the connector (resin section) with
the tool when removing and installing.
1. Remove the engine coolant temperature sensor.
2. With temperature sensing portion of engine coolant
temperature sensor immersed in hot water, check
resistance.
Standard value:
14 - 17 kΩ(at - 20_C)
5.1 - 6.5 kΩ(at 0_C)
2.1 - 2.7 kΩ(at 20_C)
0.9 - 1.3 kΩ(at 40_C)
0.48 - 0.68 kΩ(at 60_C)
0.26 - 0.36 kΩ(at 80_C)
3. If the resistance deviates from the standard value greatly,
replace the sensor.
4. Apply sealant to threaded portion.
Specified sealant:
3M NUT Locking Part No. 4171 or equivalent
5. Install the engine coolant temperature sensor and tighten
it to the specified torque.
Tightening torque: 29±9 N·m
Intake air
temperature
sensor
Engine coolant
temperature sensor
Equipment
side connector
12