MPI -General Information13A-5
MULTI-POINT FUEL INJECTION SYSTEM DIAGRAM
L1 Oxygen sensor (front)
L2 Oxygen sensor (rear)
L3 Air flow sensor
L4 Intake air temperature sensor
L5 Throttle position sensor
L6 Camshaft position sensor
L7 Crank angle sensor
L8 Barometric pressure sensor
L9 Engine coolant temperature sensor
L10 Detonation sensor
Engine-ECU
l1 Injector
l2 Idle speed control servo
l3 Fuel pressure control solenoid valve
l4 Waste gate solenoid valve
l5 EGR control solenoid valve
l6 Purge control solenoid valve
l7 Secondary air control solenoid valve
DPower supply
DIgnition switch IG
DIgnition switch ST
DVehicle speed sensor
DA/C switch
DA/C load signal
DTachometer
DPower steering fluid pressure switch
DAlternator FR terminal
DDiagnosis control terminal
DIntercooler water spray switch (automatic)
DIntercooler water spray switch (manual)DEngine control relay
DFuel pump relay 2, 3
DA/C relay
DIgnition coil
DFan controller
DCondenser fan relay (HI)
DCondenser fan relay (LOW)
DEngine warning lamp
DDiagnosis output
DAlternator G terminal
DIntercooler water spray relay
DIntercooler water spray lamp
L1 Oxygen
sensor
(front)
L4 Intake air
temperature
sensorL5 Throttle
position
sensor
L6 Camshaft
position sensorl1 Injector l2 Idle
speed
control
servo
l6 Purge
control
solenoid
valve
Three-way
catalytic converter Canister
Air
inletVacuum
tank
Fuel
pressure
reguratorFrom
fuel tank
To fuel tank
PCV valveFrom
fuel pump
Waste gate
actuatorL2 Oxygen sensor (rear) Check
valveBy-pass
valve
l5 EGR control
solenoid valve
l4 Waste gate
solenoid valve L8 Barometric
pressure
sensor
L3 Air flow
sensorl7 Secondary
air control
solenoid
valve
Secondary
air valvel3 Fuel pressure
control
solenoid valve
EGR
valve
L9 Engine coolant
temperature sensor
L7 Crank angle sensor
L10 Detonation sensor
MPI -Troubleshooting13A-9
TROUBLESHOOTING
DIAGNOSIS TROUBLESHOOTING FLOW
Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Point.
NOTE
If the engine-ECU is replaced, the immobilizer-ECU and
ignition key should be replaced together with it.
DIAGNOSIS FUNCTION
ENGINE WARNING LAMP (CHECK ENGINE LAMP)
If an abnormality occurs in any of the following items related
to the MPI system, the engine warning lamp will illuminate
or flash. If the lamp remains illuminated or if the lamp
illuminates while the engine is running, check the diagnosis
code output.
However, the warning lamp will illuminate as bulb check for
5 seconds whenever the ignition switch is turned to the ON
position.
Engine warning lamp inspection items
Code No.Diagnosis item
-Engine-ECU
P0100Air flow sensor system
P0105Barometric pressure sensor system
P0110Intake air temprature sensor system
P0115Engine coolant temperature sensor system
P0120Throttle position sensor system
P0130Oxygen sensor (front) system
P0135Oxygen sensor heater (front) system
P0136Oxygen sensor (rear) system
P0141Oxygen sensor heater (rear) system
P0201No.1 injector system
P0202No.2 injector system
P0203No.3 injector system
P0204No.4 injector system
P0325Detonation sensor system
P0335Crank angle sensor system
P0340Camshaft position sensor system
P0403EGR control solenoid valve system
Engine warning lamp
(check engine lamp)
MPI -TroubleshootingMPI -Troubleshooting13A-11
CONFIRMING FREEZE FRAME DATA
When the engine-ECU detects a malfunction and stores a diagnosis code, it also stores a current status
of the engine. This function is called “Freeze frame” data. By analyzing this “Freeze frame” data with
MUT-II, an effective troubleshooting can be performed.
NOTE
If mulfunctions have been detected in multiple systems, engine-ECU stores one malfunction only, which
has been detected first.
Item No.Data itemUnit/StateItem No.Data itemUnit/State
21Engine coolant temperature
sensor_C81Learn value%
22Crank angle sensorr/min82Feedback%
24Vehicle speedkm/h87Engine load%
FAIL-SAFE FUNCTION REFERENCE TABLE
When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled
by means of the pre-set control logic to maintain safe conditions for driving.
Malfunctioning itemControl contents during malfunction
Air flow sensor1. Uses the throttle position sensor signal and engine speed signal (crank angle sensor
signal) to take reading of the basic injector drive time and basic ignition timing from
the pre-set mapping.
2. Fixes the idle speed control servo in the appointed position so idle control is not
performed.
Intake air temperature
sensorControls as if the intake air temperature is 25_C.
Throttle position
sensorNo increase in fuel injection amount during acceleration due to the throttle position sensor
signal.
Engine coolant
temperature sensor1. Controls as if the engine coolant temperature is 80_C.
(Even after sensor signal is correctly recovered, continues until the ignition switch
is set to the “LOCK” (OFF) position.)
2. Rotates radiator fan and condenser fan at high speed.
Camshaft position
sensor1. Inject all fuel cylinders simultaneously. (However, when the No.1 cylinder top dead
centre is not detected at all after the ignition switch is turned to “ON” position.)
2. Shuts off fuel supply after 4 seconds have passed since a failure was detected.
(However, when the No.1 cylinder top dead centre is not detected at all after the
ignition switch is turned to “ON” position.)
Barometric pressure
sensorControls as if the barometric pressure is 101 kPa.
Detonation sensorSwitches the ignition timing from ignition timing for super petrol to ignition timing for standard
petrol.
Alternator FR terminalDoes not control the output of the alternator according to an electrical load. (works as a
normal alternator)
MPI -Troubleshooting13A-13
DIAGNOSTIC TROUBLE CODE INSPECTION PROCEDURE
Code No. P0100 Air flow sensor systemProbable cause
Inspection Range
DEngine speed: More than 500 r/min
Evaluation Conditions
DThe sensor output frequency is less than 3 Hz for 4 seconds.DAir flow sensor malfunction
DAir flow sensor circuit disconnection, short-circuit,
or connector contact defect
DEngine-ECU malfunction
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
MUT-IIData list
DNo. 12 Air flow sensor
(Refer to P.13A-102.)NGReplace engine-ECU.
OK
To the next pageOK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for ground wire
disconnection and damage.NG
Repair
(3) NGCheck the following connector:
C-115NG
Repair
OK
Check the harness between the air
flow sensor and engine control relay.
DCheck for power cable
disconnection and short-circuit.
(2) NGCheck the following connector:
B-11XNG
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
MUT-IIData list
DNo. 12 Air flow sensor
(Refer to P.13A-102.)NGReplace engine-ECU.
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for short-circuit of the
output wire.NG
Repair
NG
Check the following connector:
C-115NG
Repair
OK
Check and repair the harness between
the air flow sensor and engine-ECU.
DCheck for disconnection of the
output wire.NG
Repair
OK
Measure at the B-31 air flow sensor
connector.
DDisconnect the connector to
measure at the harness side
(1) Voltage between terminal No. 3
and earth
(Ignition switch: ON)
OK:4.9 - 5.1 V
(2) Voltage between terminal No. 4
and earth
(Ignition switch: ON)
OK:System voltage
(3) Resistance between terminal No.
5 and earth
OK:Less than 2Ω(1) NGMeasure at the C-115 engine-ECU
connector.
DMeasure the voltage of the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal No. 90
and earth.
OK:4.9 - 5.1 VOKCheck the following connector:
C-115
NG
Check the following connector:
B-31NG
Repair
MUT-IIData list
DNo. 12 Air flow sensor
(Refer to P.13A-102.)OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
Repair
MPI -Troubleshooting13A-14
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for damage of the output
wire.
DCheck for damage of the earth
wire.NG
OK
Check the harness between the air
flow sensor and engine control relay.
DCheck for damage of the power
cable.Repair NG
NG
Check the following connectors:
B-11X, C-115Repair OK
Check the trouble symptom.End
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
MUT-IIData list
DNo. 12 Air flow sensor
(Refer to P.13A-102.)NGReplace engine-ECU.
Replace the air flow sensor.
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
Measure the output waveform at the
B-31 air flow sensor connector (using
an analyzer).
DUsing the test harness
(MB991709), connect the
connector, and measure at the
pickup harness.
DEngine: Idle
DVoltage between terminal No. 3
and earth.
OK:Output the waveform as
shown on P.13A-112 (in-
spection procedure by ana-
lyzer), and check that there
is noise in the output wave-
form.NG
OK
MUT-IIData list
DNo. 12 Air flow sensor
(Refer to P.13A-102.)NGReplace engine-ECU.
OK
Check the harness between air flow
sensor and engine-ECU.
DCheck for disconnection and
damage of the reset signal wire.NG
Repair
OK
Measure at the B-31 air flow sensor
connector.
DUsing the test harness
(MB991709), connect the
connector, and measure at the
pickup harness.
DVoltage between terminal No. 7
and earth.
OK:Engine: idle
0-1V
Engine: 3,000 r/min
6-9VNGCheck the following connector:
C-126NGRepair
OK
Replace the air flow sensor.
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for short-circuit of the
reset signal wire.NG
Repair
OK
Measure at the B-31 air flow sensor
connector.
DUsing the test harness
(MB991709), connect the
connector, and measure at the
pickup.
DIgnition switch: ON
DVoltage between terminal No. 7
and earth.
OK:7-8VNGCheck the following connector:
C-126NGRepair
From the previous page
MPI -Troubleshooting13A-15
Code No. P0105 Barometric pressure sensor systemProbable cause
Inspection Range
D2 seconds after the ignition switch is set to the “ON” position, or after the
completion of start of engine.
Evaluation Conditions
DThe sensor output voltage is more than 4.5 V for 4 seconds (Equivalent to
air pressure of more than 114 kPa)
or
DThe sensor output voltage is less than 0.2 V for 4 seconds (Equivalent to air
pressure of less than 5 kPa)DBarometric pressure sensor malfunction
DBarometric pressure sensor circuit disconnection,
short-circuit, or connector contact defect
DEngine-ECU malfunction
OK
To the next page
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
MUT-IIData list
DNo. 25 Barometric pressure
sensor (Refer to P.13A-103.)NGReplace engine-ECU.
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck the earth wire for
disconnection and damage.NG
Repair
(2) NGCheck the following connector:
C-115NG
Repair
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
MUT-IIData list
DNo. 25 Barometric pressure
sensor (Refer to P.13A-103.)NGReplace engine-ECU.
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for short-circuit of the
power cable.NG
Repair
NG
Check the following connector:
C-115NG
Repair
OK
Check and repair the harness between
the air flow sensor and engine-ECU.
DCheck for disconnection of the
power cable.NG
Repair
OK
Measure at the B-31 air flow sensor
connector.
DDisconnect the connector to
measure at the harness side
(1) Voltage between terminal No. 1
and earth
(Ignition switch: ON)
OK:4.9 - 5.1 V
(2) Resistance between terminal No.
5 and earth.
OK:Less than 2Ω(1) NGMeasure at the C-115 engine-ECU
connector.
DMeasure the engine-ECU terminal
voltage.
DIgnition switch: ON
DVoltage between terminal No. 81
and earth
OK:4.9 - 5.1 VOKCheck the following connector:
C-115
NG
Check the following connector:
B-31NG
Repair
MUT-IIData list
DNo. 25 Barometric pressure
sensor (Refer to P.13A-103.)OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
MPI -Troubleshooting13A-16
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
MUT-IIData list
DNo. 25 Barometric pressure
sensor (Refer to P.13A-103.)NGReplace engine-ECU.
OK
Check the following connector:
C-115NG
Repair
OK
Check and repair the harness between
the air flow sensor and engine-ECU.
DCheck for disconnection and
damage of the output wire.
OK
Measure at the C-115 engine-ECU
connector.
DMeasure the engine-ECU terminal
voltage.
DIgnition switch: ON
DVoltage between terminal No. 85
and earth.
OK:High 0 m 3.8 - 4.2 V
High 600 m 3.5 - 3.9 V
High 1,200 m 3.3 - 3.7 V
High 1,800 m 3.0 - 3.4 VNGCheck the following connector:
C-115NGRepair
OK
Replace the air flow sensor.
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for short-circuit and
damage of the output wire.NG
Repair
(3) NGCheck the following connector:
C-115NG
Repair
OK
Check and repair the harness between
the air flow sensor and engine-ECU.
DCheck for damage of the power
cable.
DCheck for damage of the earth
wire.
OK
Measure at the B-31 air flow sensor
connector.
DUsing the test harness
(MB991709), connect only
connector terminals No. 1, No. 2,
and No. 5, and measure at the
pickup harness.
DIgnition switch: ON
(1) Voltage between terminal No. 1
and earth
OK:4.9 - 5.1 V
(2) Voltage between terminal No. 5
and earth
OK:Less than 0.5 V
(3) Voltage from No. 2 to earth
OK:High 0 m 3.8 - 4.2 V
High 600 m 3.5 - 3.9 V
High 1,200 m 3.3 - 3.7 V
High 1,800 m 3.0 - 3.4 V(1), (2) NGCheck the following connectors:
C-115NGRepair
From the previous page
Code No. P0110 Intake air temperature sensor systemProbable cause
Inspection Range
DAfter setting the ignition switch to the “ON” position, or after 2 seconds from
completion of start.
Evaluation Conditions
DThe sensor output voltage is more than 4.6 V for 4 seconds (Equivalent to intake
air temperature less than - 40_C)
or
DThe sensor output voltage is less than 0.2 V for 4 seconds (Equivalent to intake
air temperature of more than 120_C)DIntake air temperature sensor malfunction
DIntake air temperature sensor circuit disconnection,
short-circuit, or connector contact defect
DEngine-ECU malfunction
MPI -Troubleshooting13A-17
OK
Check the intake air temperature
sensor alone. (Refer to P.13A-132.)NGReplace the intake air temperature
sensor.
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
To the next page
OK
Intermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
MUT-IIData list
DNo. 13 intake air temperature
sensor
OK:Ambient temperature (More
or less the same as air
temperature)NGReplace engine-ECU.
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for short-circuit of the
output wire.NG
Repair
OK
Check and repair the harness between
the air flow sensor and engine-ECU.
DCheck for disconnection of the
output wire.NG
Repair
NG
Check the following connector:
C-115NG
Repair
(2) NGMeasure at the C-115 engine-ECU
connector.
DMeasure the engine-ECU terminal
voltage.
DDisconnect the B-31 air flow
sensor connector.
DIgnition switch: ON
DVoltage between terminal No. 72
and earth.
OK:4.5 - 4.9 VOKCheck the following connector:
C-115
OK
MUT-IIData list
DNo. 13 Intake air temperature
sensor
OK:Ambient temperature (More
or less the same as the air
temperature)NGReplace the engine-ECU.
OK
Check the harness between the air
flow sensor and engine-ECU.
DCheck for disconnection and
damage of the earth wire.NG
Repair
OK
Measure at the B-31 air flow sensor
connector.
DDisconnect the connector to
measure at the harness side
(1) Resistance between terminal No.
5 and earth
OK:Less than 2Ω
(2) Voltage between terminal No. 6
and earth
(Ignition switch: ON)
OK:4.5 - 4.9 V(1) NGCheck the following connector:
C-115NGRepair
NG
Check the following connector:
B-31NG
Repair
MUT-IIData list
DNo. 13 Intake air temperature
sensor
OK:Ambient temperature (More
or less the same as the air
temperature)OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)