
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-36
OK
Intermittent Malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunction.)
OK
MUT-IIData list
DNo. 22 Crank angle sensor
(Refer to P.13A-103.)NGReplace the engine-ECU.
OK
Intermittent Malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunction.)
OK
Check the trouble symptos.NGReplace the crank angle sensor.
OK
Check for crank angle sensor vane.NGReplace the crank angle sensor vane. NG
OK
Check the harness between the crank
angle sensor and body earth.
DCheck for damage of the earth
wire.Repair NG
OK
Check the harness between the crank
angle sensor and engine-ECU.
DCheck for damage of the output
wire.Reapir NG
OK
Check the following connector:
C-115Repair NG
OK
Check the harness between the crank
angle sensor and engine control relay.
DCheck for damage of the power
cable.Repair
OK
Measure the output waveform at the
B-121 crank angle sensor connector
(using an analyzer).
DUsing the test harness
(MD998478), connect the
connector, and measure at the
pickup harness.
DEngine: Idle
DVoltage between terminal No.2 and
earth.
OK:The waveform shown on
P.13A-117 (Inspection Proce-
dure Using Analyzer), should
be output,and the maximum
value should be more than
4.8 V, and the minimum value
less than 0.6 V. No noise
should be detected in the
output waveform.NGCheck the following connector:
B-11XNG
Repair
From the previous page

MPI -Troubleshooting13A-38
OK
Intermittent Malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunction.)
OK
Check the trouble symptoms.NGReplace the engine-ECU.
OK
Intermittent Malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunction.)
OK
Check the trouble symptos.NGReplace the camshaft position sensor.
OK
Check the camshaft position sensing
cylinder.NGReplace the camshaft position sensing
cylinder. NG
OK
Check the harness between the
camshaft position sensor and body
earth.
DCheck for damage of the earth
wire.Repair NG
OK
Check the harness between the
camshaft position sensor and
engine-ECU.
DCheck for damage of the output
wire.Reapir NG
OK
Check the following connector:
C-115Repair NG
OK
Check the harness between the
camshaft position sensor connector
and engine control relay.
DCheck for damage of the power
cable.Repair
OK
Measure the output waveform at the
B-116 camshaft position 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. 2
and earth.
OK:The waveform shown on
P.13A-117 (Inspection Proce-
dure Using Analyzer), should
be output,and the maximum
value should be more than
4.8 V, and the minimum value
less than 0.6 V. No noise
should be detected in the
output waveform.NGCheck the following connector:
B-11XNG
Repair
From the previous page

MPI -Troubleshooting13A-44
Code No. P0505 Idle speed control systemProbable cause
Range of Check
DVehicle speed has reached 1.5 Km/h at least once.
DUnder the closed loop idle speed control.
Set Conditions
DActual idle speed has continued to be higher than the target idle speed by 300
r/min or more for 10 seconds.
Range fo Check
DVehicle speed has reached 1.5 km/h at least once.
DDuring idle speed closed loop control.
DThe highest temperature at the last drive is 45_C or less.
DEngine coolant temperature is approximately 80_C or more.
DBattery voltage is 10 V or more.
DBarometric pressure is 76 kPa or higher.
DIntake air temperature is - 10_C or more.
Set Conitions
DActual idle speed has been minimum 200 r/min higher than the target idle speed
for 10 seconds.
Range of Check
DDuring idle speed closed loop control.
DEngine coolant temperature is approximately 80_C or higher.
DBattery voltage is 10 V or higher.
DPower steering switch is off.
DVolumetric efficiency is 40 % or lower.
DBarometric pressure is 76 kPa or higher.
DIntake air temperature is - 10_C or more.
Set Conitions
DActual idle speed has been minimum 100 r/min higher than the target idle speed
for 10 seconds.DMalfunction of idle speed control servo
DOpen or short circuit in the idle speed control servo
circuit or loose connector contact
DMalfunction of engine-ECU

MPI -Troubleshooting13A-45
OKNG
OK
NG
Check and repair the harness
between the idle speed control servo
and engine control relay.
DCheck for disconnection and
short-circuit of the power cable.
OK
Measure at the B-115 idle speed
control servo connector.
DDisconnect the connector to
measure at the harness side.
DIgnition switch: ON
DVoltage between terminal No. 2
and earth
DVoltage between terminal No. 5
and earth
OK:System voltageOKCheck the following connector:
B-11XNG
NG
OK
Measure at the B-115 idle speed
control servo connector.
DDisconnect the connector to
measure at the idle speed control
servo side.
DResistance between terminal No.
1 and terminal No. 2
DResistance between terminal No.
2 and terminal No. 3
DResistance between terminal No.
4 and terminal No. 5
DResistance between terminal No.
5 and terminal No. 6
OK:28 - 33ΩReplace the idle speed control servo.
Check the following connector:
B-115NG
Repair
NGCheck the harness between the idle speed control servo and
engine-ECU.
DCheck for damage of the output cable.OK
Repair
NGRepair OK
OKRepair
NG
Repair
OK
OK
Check the harness between the idle
speed control servo and engine-ECU.
DCheck for disconnection and
short-circuit of the output cable.NG
Repair
Check the following connector:
C-126
NG
Replace the engine-ECU.
OKIntermittent malfunction (Refer to
GROUP 00 - Points to Note for
Intermittent Malfunctions.)Check the trouble symptoms.
Measure at the C - 126 engine-ECU
connector.
DMeasure the engine-ECU terminal
voltage.
DVoltage between terminal No. 4
and earth
DVoltage between terminal No. 5
and earth
DVoltage between terminal No. 17
and earth
DVoltage between terminal No. 18
and earth
OK:After the warmed engine
completes starting, the volt-
age repeatedly fluctuates
as shown below.
System voltage↔0-6V
OK
Check the following connector:
C-126NG
Repair
Check the harness between the idle sped control servo and
engine control relay.
DCheck for damage of the power cable.
NG
Replace the engine-ECU.
OKIntermittent malfunction (Refer to
GROUP 00 - Points to Note for
Intermittent Malfunctions.)Check the trouble symptoms.

MPI -Troubleshooting
Fig. 1
Vehicle
speedInitial ac-
celerator
pedal de-
pressionNormalHesitation
Sag
TimeFig. 2
Normal
Initial ac-
celerator
pedal de-
pression
IdlingStumble
Time Vehicle
speed
13A-53
PROBLEM SYMPTOMS TABLE (FOR YOUR INFORMATION)
ItemsSymptom
StartingWon’t startThe starter is used to crank the engine, but there is no combustion within the
cylinders, and the engine won’t start.
Fires up and diesThere is combustion within the cylinders, but then the engine soon stalls.
Hard startingEngine starts after cranking a while.
Idling
stability
HuntingEngine speed doesn’t remain constant; changes at idle.
stability
Rough idleUsually, a judgement can be based upon the movement of the tachometer
pointer, and the vibration transmitted to the steering wheel, shift lever, body, etc.
This is called rough idle.
Incorrect idle speedThe engine doesn’t idle at the usual correct speed.
Engine stall
(Die out)The engine stalls when the foot is taken from the accelerator pedal, regardless
of whether the vehicles is moving or not.
Engine stall
(Pass out)The engine stalls when the accelerator pedal is depressed or while it is being
used.
DrivingHesitation Sag“Hesitation” is the delay in response of the vehicle speed (engine speed) that
occurs when the accelerator is depressed in order to accelerate from the speed
at which the vehicle is now traveling, or a temporary drop in vehicle speed
(engine speed) during such acceleration.
Serious hesitation is called “sag”. (Refer to Fig. 1)
Poor accelerationPoor acceleration is inability to obtain an acceleration corresponding to the
degree of throttle opening, even though acceleration is smooth, or the inability
to reach maximum speed.
StumbleEngine speed increase is delayed when the accelerator pedal is initially
depressed for acceleration. (Refer to Fig. 2)
ShockThe feeling of a comparatively large impact or vibration when the engine is
accelerated or decelerated.
SurgeThis is repeated surging ahead during constant speed travel or during variable
speed travel.
KnockingA sharp sound like a hammer striking the cylinder walls during driving and which
adversely affects driving.
StoppingRun on
(“Dieseling”)The condition in which the engine continues to run after the ignition switch is
turned to “LOCK” (OFF) position. Also called “Dieseling”.

MPI -Troubleshooting13A-61
Inspection Procedure 7
Starting disabled (Initial combustion occurs but is
incomplete.), improper starting (Starting time is long.)
Probable cause
Causes shown on right are suspected.DBattery malfunction
DIgnition system malfunction
DFuel system malfunction
DIntake system malfunction
DEGR valve malfunction
DTiming belt malfunction
DImproper compression pressure
DEngine-ECU malfunction
OK
To the next page
OK
Check and repair the harness between
the engine-ECU and earth joint.
DCheck for disconnection and
damage of the earth cable.
(2) NGCheck the following connector:
C-126NG
Repair
NG
Replace the engine-ECU.
OK
Check the trouble symptoms.OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.) NG
OK
Check the harness between the
engine-ECU and battery.
DCheck for disconnection,
short-circuit and damage of the
power cable.Repair
OK
Measure at the C-115 and C-126 en-
gine-ECU connectors.
DMeasure the engine-ECU terminal
voltage.
(1) Voltage between terminal No. 80
and earth
OK:System voltage
(2) Voltage between terminal No. 13
and earth
Voltage between terminal No. 26
and earth
(Ignition switch: ON)
OK:0.5 V or less(1) NGCheck the following connectors:
C-115, C-129, C-05, C-135NG
Repair
OK
Check the timing marks on the timing belt.NGAlign the timing marks on the timing belt.
OK
Check the air intake from the intake hose and intake manifold.NG
Repair
NO
MUT-IIData list
DNo. 13: Intake air temperature sensor
DNo. 21: Engine coolant temperature sensor
DNo. 25: Barometric pressure sensor
(Refer to P.13A-102.)
Proceed to OK if all service data values are correct.
Proceed to NG if there is even one abnormal service data value.NGRefer to inspections for diagnosis code of sensor showing abnormal
service data. (Refer to P.13A-12.)
OK
MUT-IISelf-Diag code
DIs a diagnosis code output?YESINSPECTION CHART FOR DIAGNOSIS CODE
(Refer to P.13A-12.)
NO
Check the battery. (Refer to GROUP 54 - Battery.)NGReplace the battery.
Has the battery terminal been disconnected recently?YESAfter warming up the engine, idle for approximately 10 minutes.

MPI -Troubleshooting13A-63
Inspection Procedure 8
Unstable idling (Rough idling, hunting), inappropriate
idling speed (High or low idling speed), engine stalls (Die
out) during idling
Probable cause
Causes shown on right are suspected.DIdle speed control system malfunction
DAir/fuel ratio control system malfunction
DIgnition system malfunction
DFuel system malfunction
DIntake and exhaust system malfunction
DExhaust gas purifier system malfunction
DThrottle valve malfunction
DTiming belt malfunction
DImproper compression pressure
DEngine-ECU malfunction
OK
To the next page
OK
MUT-IIData list
DNo. 11: Oxygen sensor (front) (Refer to P.13A-102.)NGCheck the Code No. P0130: Oxygen sensor (front) system.
(Refer to P.13A-24.)
OK
Check the throttle body (throttle valve section) for contamination.NGClean the throttle body (throttle valve section).
(Refer to P.13A-126.)
OK
Check the air intake from the intake hose and intake manifold.NG
Repair
OK
Check the timing marks on the timing belt.NGAlign the timing marks on the timing belt.
OK
MUT-IIData list
DNo. 27: Power steering fluid pressure switch
(Refer to P.13A-103.)NGCheck the Power steering fluid pressure switch system. (Refer to
P.13A-51, PROCEDURE FOR DAIGNOSIS CODE P0551)
OK
MUT-IIData list
DNo. 45: Idle speed control servo position (Refer to P.13A-105.)NGCheck the Idle speed control servo (stepper motor) system. (Refer
to P.13A - 49 PROCEDURE FOR DIAGNOSIS CODE P0505)
NO
MUT-IIData list
DNo. 12: Air flow sensor
DNo. 13: Intake air temperature sensor
DNo. 14: Throttle position sensor
DNo. 21: Engine coolant temperature sensor
DNo. 25: Barometric pressure sensor
(Refer to P.13A-102.)
Proceed to OK if all service data values are correct.
Proceed to NG if there is even one abnormal service data value.NGRefer to inspections for diagnosis code of sensor showing abnormal
service data. (Refer to P.13A-12.)
NO
MUT-IISelf-Diag code
DIs a diagnosis code output?YESINSPECTION CHART FOR DIAGNOSIS CODE
(Refer to P.13A-12.)
Has the battery terminal been disconnected recently?YESAfter warming up the engine, idle for approximately 10 minutes.