Page 642 of 1449

MPI -Troubleshooting13A-110
Terminal No.Normal condition Check condition (Engine condition) Check item
12Power supplyIgnition switch: “ON”System voltage
25
19Air flow sensor reset
signal
Engine: Idle operation0-1V
signal
Engine speed: 3,000 r/min6-9V
21Fan controllerRadiator fan is not operating0 - 0.3 V
Radiator fan is operating0.7 V or more
22Fuel pump relay 2Ignition switch: “ON”System voltage
Engine: Idle operation1 V or less
24A/C load signalDEngine:
Idle operation
DA/C switch: ON
(A/C compressor
runs)DOutdoor air
sensor ambient
temperature:
18_C or more
DA/C setting
temperature:
Minimum
temperature
DA/C air volume:
Maximum1 V or less
DA/C setting
temperature:
indoor
temperature
DA/C air volume:
MinimumSystem voltage
32Condenser fan motor
relay (HI)Fan inactive state
(Engine coolant temperature: 90_C or less)System voltage
Fan high-speed rotation state
(Engine coolant temperature: 105_C or more)1 V or less
33Alternator G terminalDEngine: After warm-up, idle operation
DRadiator fan: Not operating
DHeadlamp: OFF→ON
DStop lamp: OFF→ON
DRear defogger switch: OFF→ONVoltage increases by
0.2 - 3.5 V
34Condenser fan motor
relay (LOW)Fan inactive state
(Engine coolant temperature: 90_C or less)System voltage
Fan low-speed rotation state (Engine coolant
temperature: 95 - 100_C or more)1 V or less
35Intercooler water
spraylamp
Ignition switch: “ON”System voltage
spraylamp
Ignition switch: “LOCK” (OFF)1 V or less
36Engine warning lampIgnition switch: “LOCK” (OFF)→“ON”1 V or less→System
voltage (After several se-
conds have elapsed)
Page 644 of 1449

MPI -Troubleshooting13A-112
Terminal No.Normal condition Check condition (Engine condition) Check item
72Intake air
temperature sensorIgnition switch: “ON”Intake air
temperature: - 20_C3.8 - 4.4 V
Intake air
temperature: 0_C3.2 - 3.8 V
Intake air
temperature: 20_C2.3 - 2.9 V
Intake air
temperature: 40_C1.5 - 2.1 V
Intake air
temperature: 60_C0.8 - 1.4 V
Intake air
temperature: 80_C0.4 - 1.0 V
75Oxygen sensor
(Rear)DTransmission: Second gear
DDriving with the throttle widely open
DEngine: 3,500 r/min or more0.6 - 1.0 V
76Oxygen sensor (front)Engine: Running at 2,500 r/min after warmed
up (Check using a digital type voltmeter)0↔0.8 V
(Changes repeatedly)
80Backup power supplyIgnition switch: “LOCK” (OFF)System voltage
81Sensor impressed
voltageIgnition switch: “ON”4.9 - 5.1 V
82Ignition switch - IGIgnition switch: “ON”System voltage
83Engine coolant
temperature sensorIgnition switch: “ON”Coolant temperature:
-20_C3.9 - 4.5 V
Coolant temperature:
0_C3.2 - 3.8 V
Coolant temperature:
20_C2.3 - 2.9 V
Coolant temperature:
40_C1.3 - 1.9 V
Coolant temperature:
60_C0.7 - 1.3 V
Coolant temperature:
80_C0.3 - 0.9 V
84Throttle position
sensorIgnition switch: “ON”Set throttle valve to
idle position0.535 - 0.735 V
Fully open throttle
valve4.5 - 5.0 V
85Barometric pressure
sensor
Ignition switch: “ON”Altitude: 0 m3.8 - 4.2 V
sensor
Altitude: 600 m3.5 - 3.9 V
Altitude: 1,200 m3.2 - 3.8 V
Altitude: 1,800 m3.0 - 3.4 V
Page 647 of 1449

MPI -Troubleshooting13A-115
Terminal No. Normal condition (Check condition)Inspection item
3-12Fuel pressure control solenoid valve28 - 36Ω(at 20_C)
4-12Stepper motor coil (A1)28 - 33Ω(at 20_C)
17 - 12Stepper motor coil (A2)
5-12Stepper motor coil (B1)
18 - 12Stepper motor coil (B2)
6-12EGR control solenoid valve36 - 44Ω(at 20_C)
9-12Purge control solenoid valve22 - 26Ω(at 20_C)
11 - 1 2Waste gate solenoid valve62 - 74Ω(at 20_C)
13 - Body earthENGINE-ECU earthContinuity (0Ω)
26 - Body earthENGINE-ECU earth
53 - 12Secondary air control solenoid valve28 - 36Ω(at 20_C)
54 - 12Oxygen sensor heater (Rear)11 - 1 8Ω(at 20_C)
60 - 12Oxygen sensor heater (Front)4.5 - 8.0Ω(at 20_C)
72 - 92Intake air temperature sensor13 - 17 kΩ(When intake air temperature is - 20_C)
5.7 - 6.7 kΩ(When intake air temperature is 0_C)
2.3 - 3.0 kΩ(When intake air temperature is 20_C)
1.0 - 1.5 kΩ(When intake air temperature is 40_C)
0.56 - 0.76 kΩ(When intake air temperature is 60_C)
0.30 - 0.42 kΩ(When intake air temperature is 80_C)
83 - 92Engine coolant temperature sensor14 - 17 kΩ(When coolant temperature is - 20_C)
5.1 - 6.5 kΩ(When coolant temperature is 0_C)
2.1 - 2.7 kΩ(When coolant temperature is 20_C)
0.9 - 1.3 kΩ(When coolant temperature is 40_C)
0.48 - 0.68 kΩ(When coolant temperature is 60_C)
0.26 - 0.36 kΩ(When coolant temperature is 80_C)
Page 653 of 1449

MPI -Troubleshooting13A-121
IDLE SPEED CONTROL SERVO (STEPPER MOTOR)
Measurement Method
1. Disconnect the idle speed control servo connector, and
connect the special tool (test harness: MB991709) in
between.
2. Connect the analyzer special patterns pickup to the idle
speed control servo-side connector terminal No. 1,
terminal No. 3, terminal No. 4 and terminal No. 6
respectively.
Alternate Method (Test harness not available)
1. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 4, connection terminal No. 5,
connection terminal No. 17, and connection terminal No.
18 respectively.
Standard Wave Pattern
Observation conditions
FunctionSpecial patterns
Pattern heightHigh
Pattern selectorDisplay
Engine conditionWhen the engine coolant temperature is 20_C or below, turn the ignition switch from “LOCK”
(OFF) position to “ON” position (without starting the engine).
While the engine is idling, turn the A/C switch to ON.
Immediately after starting the warm engine
Standard wave pattern
Stepper
motor
control
signal
wave
pattern(V)
30
20
10The wave pattern
appears for an
instant, but soon
disappears.Point B
Coil reverse electromotive
force (Approx. 3×10 V)Point A
Induced electromotive force
from the motor turning
Time
Special
patterns
pickupAnalyzer
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 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
Page 666 of 1449

MPI -On-vehicle Service13A-134
THROTTLE POSITION SENSOR CHECK
1. Disconnect the throttle position sensor connector.
2. Measure the resistance between the throttle position
sensor side connector terminal No. 1 and terminal No.
4.
Standard value: 3.5 - 6.5 kΩ
3. Measure the resistance between the throttle position
sensor side connector terminal No. 2 and terminal No.
4.
Normal condition:
Throttle valve slowly open
until fully open from the idle
positionChanges smoothly in
proportion to the opening
angle of the throttle valve
4. If the resistance is outside the standard value, or if it
doesn’t change smoothly, replace the throttle position
sensor.
NOTE
For the throttle position sensor adjustment procedure,
refer to P.13A-90.
OXYGEN SENSOR CHECK
1. Disconnect the oxygen sensor connector and connect
the special tool (test harness: MB998464) to the connector
on the oxygen sensor side.
2. Make sure that there is continuity (4.5 - 8.0Ωat 20_C)
between terminal No. 1 and terminal No. 3 on the oxygen
sensor connector.
3. If there is no continuity, replace the oxygen sensor.
4. Warm up the engine until engine coolant is 80_C or higher.
Equipment side connector
Throttle
bodyThrottle
position
sensor
Oxygen
sensor
(front)
Equipment
side connector
1
32
4
Oxygen
sensor
(front)
equipment
side
conenctor
MD998464 BlueRed
Page 670 of 1449

MPI -On-vehicle Service13A-138
RESISTOR (FOR INJECTOR) CHECK
1. Disconnect the resistor connector.
2. Measure the resistance between each terminal.
Standard value:
Measurement terminalResistanceΩ
1-35.8 - 6.2 (at 20_C)
4-3
5-3
6-3
IDLE SPEED CONTROL SERVO (STEPPER
MOTOR) CHECK
Checking the Operation Sound
1. Check that the engine coolant temperature is 20_Cor
below.
NOTE
Disconnecting the engine coolant temperature sensor
connector and connecting the harness-side of the
connector to another engine coolant temperature sensor
that is at 20_C or below is also okay.
2. Check that the operation sound of the stepper motor
can be heard after the ignition is switched “ON” position.
(but without starting the engine.)
3. If the operation sound cannot be heard, check the stepper
motor’s activation circuit.
If the circuit is normal, it is probable that there is a
malfunction of the stepper motor or of the engine-ECU.
Resistor
(for injector)
Fuel pump relay 3
1
42
53
6
Equipment
side connector
Idle speed control
servo (stepper motor) 1
42
53
6