MPI -Troubleshooting13A-104
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
25Barometric
pressure
Ignition switch: ONAltitude: 0 m101 kPaCode No.
P0105
13A-15
pressure
sensor
Altitude: 0 m95 kPa
P0105
Altitude: 0 m88 kPa
Altitude: 0 m81 kPa
27Power
steering
fluidEngine: Idle operationSteering wheel
stationaryOFFCode No.
P055113A-46
fluid
pressure
switchSteering wheel turningON
28A/C switchEngine: Idle operation
(When A/C switch isA/C switch: OFFOFFProcedure
No. 2613A-92
(WhenA/Cswitchis
ON, A/C compressor
should be operating.)A/C switch: ONON
No.26
34Air flow
sensorEngine: After
warm-upIdle operationONCode No.
P010013A-13
sensor
reset
signal
warm up
3,000 r/minOFF
P0100
37Volumetric
efficiency
DEngine coolant
temperature:
Idle operation15 - 35%--
efficiencytemperature:
85 - 95_C
DLightningand
2,500 r/min15 - 35%
DLightning and
accessories:
OFFExcessive
accellerationAccording to ac-
celeration, volu-
metric efficiency
is increased.
41Injectors*1Engine: CrankingWhen engine coolant
temperature is 0_C
(injection is carried out
for all cylinders simulta-
neously)25 - 37 ms--
When engine coolant
temperature is 20_C15 - 22 ms
When engine coolant
temperature is 80_C4.2 - 6.3 ms
Injectors*2DEngine coolant
temperature:
80–95_C
Engine: Idle operation1.5 - 2.7 ms--
80–95_C
DLamps, electric
cooling fan and
allaccessories:
2,500 r/min1.2 - 2.4 ms
allaccessories:
OFF
DTransmission:
Neutral
When engine is sud-
denly racedIncreases
MPI -Troubleshooting13A-111
Terminal No.Normal condition Check condition (Engine condition) Check item
37Power steering fluid
pressure switchEngine: Idling after
warming upWhen steering wheel
is stationarySystem voltage
When steering wheel
is turned1 V or less
38Engine control relayIgnition switch: “LOCK” (OFF)System voltage
Ignition switch: “ON”1 V or less
39Fuel pump relay 3While engine is idling, suddenly depress the
accelerator pedal.Temporarily rises slightly
from 1 V or less.
41Alternator FR
terminalDEngine: After warm-up, idle operation
DRadiator fan: Not operating
DHead lamp: OFF→ON
DStop lamp: OFF→ON
DRear deffogger switch: OFF→ONVoltage decrease
44Intercooler water
spray switch (Auto)DIgnition switch: “ON”
DIntercooler water spray switch: ON1 V or less
DIgnition switch: “ON”
DIntercooler water spray switch: OFFSystem voltage
45A/C switchEngine: Idle operationTurn the A/C switch
OFF0.5 V or less
DA/C switch: ON
DA/C setting
temperature
When room tem-
perature is 25_C
or more: Max
Cool
When room tem-
perature is 25_C
or less: Max. HotSystem voltage
53Secondary air control
solenoid valveIgnition switch: “ON”System voltage
54Oxygen sensor
heater(Rear)
Engine: Idling after warming up1 V or less
heater(Rear)
Engine speed: 5,000r/minSystem voltage
55Intercooler water
sprayrelay
Ignition switch: “ON”System voltage
spray relay
Ignition switch: “LOCK” (OFF)1 V or less
58Tachometer signalEngine speed: 3,000r/min0.3 - 3.0 V
60Oxygen sensor
heater(front)
Engine: Idling after warming up1 V or less
heater(front)
Engine speed: 5,000r/minSystem voltage
71Ignition switch - STEngine: Cranking8 V or more
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
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
ENGINE ELECTRICAL -Ignition System16-26
IGNITION SYSTEM
GENERAL INFORMATION
This system is equipped with two ignition coils (A
and B) with built-in power transistors for the No.
1 and No. 4 cylinders and the No. 2 and No. 3
cylinders respectively.
Interruption of the primary current flowing in the
primary side of ignition coil A generates a high
voltage in the secondary side of ignition coil A.
The high voltage thus generated is applied to the
spark plugs of No. 1 and No. 4 cylinders to generate
sparks. At the time that the sparks are generated
at both spark plugs, if one cylinder is at the
compression stroke, the other cylinder is at the
exhaust stroke, so that ignition of the compressed
air/fuel mixture occurs only for the cylinder which
is at the compression stroke.
In the same way, when the primary current flowing
in ignition coil B is interrupted, the high voltage
thus generated is applied to the spark plugs of
No. 2 and No. 3 cylinders.
The Engine-ECU turns the two power transistors
inside the ignition coils alternately on and off. Thiscauses the primary currents in the ignition coils
to be alternately interrupted and allowed to flow
to fire the cylinders in the order 1-3-4-2.
The Engine-ECU determines which ignition coil
should be controlled by means of the signals from
the camshaft position sensor which is incorporated
in the camshaft and from the crank angle sensor
which is incorporated in the crankshaft. It also
detects the crankshaft position in order to provide
ignition at the most appropriate timing in response
to the engine operation conditions. It also detects
the crankshaft position in order to provide ignition
at the most appropriate timing in response to the
engine operation conditions.
When the engine is cold or operated at high
altitudes, the ignition timing is slightly advanced
to provide optimum performance.
When the automatic transmission shifts gears, the
ignition timing is also retarded in order to reduce
output torque, thereby alleviating shifting shocks.
SYSTEM DIAGRAM
Barometric pressure sensor
Intake air temperature sensor
Engine coolant temperature sensor
Camshaft position sensor
Crank angle sensor
Ignition switch - ST
Vehicle speed signalEngine-ECU
Ignition coil A
Ignition coil B Ignition switch
Spark plugBattery
To tachometerCylinder No. Air flow sensor
1 4
23
Detonation sensor
MANUAL TRANSMISSION - Troubleshooting
INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis
code No.Diagnosis itemsReference page
12Power supply voltage (valve power supply) systemopen circuit or short-circuit22A-8
13Fail-safe relay system
21Wheel speed sensor
22Wheel speed sensor
23Wheel speed sensor
24Wheel speed sensor
25Wrong-diameter tire22A-11
26Wheel speed sensor (faulty output signal)22A-13
31Steering wheel sensor
32Steering wheel sensor
33fixed22A-16
34Steering wheel sensor
fixed22A-17
41TPS systemopen circuit or ground22A-18
42short-circuit22A-18
45Pressure sensor systemopen circuit or ground22A-19
46open earth22A-19
47abnormal power supply22A-20
51Longitudinal G sensor systemopen circuit or short-circuit22A-21
52defective sensor22A-22
56Lateral G sensor systemopen circuit or short-circuit22A-23
57defective sensor22A-24
61Stop lamp switch systemopen circuit22A-25
62ACD mode switch systemstuck22A-26
63Parking brake switch systemshort-circuit or not re-
turned to original position22A-27
65ABS monitor systemopen circuit or defective
ABS22A-28
71Proportional valve
GROUP27B
72Directional control valve
GROUP27B.
73Directional control valve
74Proportional valve
MANUAL TRANSMISSION - Troubleshooting
Code No.34 Steering wheel sensor
Code No.34 is output when no change in the steering wheel sensor signal at a
vehicle speed of above 15 km/h is detected for a total of more than 15 minutes
DSteering wheel sensor fault
D4WD-ECU fault
NG
OK
MUT-IIData List
DNo.53 Steering wheel sensor
OK:When the steering wheel is rotated to the left, ON
and OFF are repeated.
DNo.54 Steering wheel sensor
OK:When the steering wheel is rotated to the right, ON
and OFF are repeated.
OK→Intermittent malfunction (Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions)
Check the following connector:C-43
NG→Repair
NG
Check the following connectors:
NG→Repair
OK
Replace the steering wheel sensor.OK
OK
Check the harness between the 4WD-ECU and steering wheel
sensor.
DCheck for damage of the output line.
Check the harness between the steering wheel sensor and
body earth.
DCheck for open circuit and damage of the earth line.
NG→Repair
Measure at 4WD-ECU connector C-43.
DMeasure the ECU terminal voltage.
DIgnition switch: ON
(1) Voltage between terminal 33 and earth (Steering wheel
sensor
(2) Voltage between terminal 34 and earth (Steering wheel
sensor
OK:When the steering wheel is turned, changes at
approx. 1.5 V or 3.5 V
MUT-IIData List
DNo.53 Steering wheel sensor
OK:When the steering wheel is rotated to the left, ON
and OFF are repeated
DNo.54 Steering wheel sensor
OK:When the steering wheel is rotated to the right ON
and OFF are repeated.
NG→Replace the 4WD-ECU.
OK→Intermittent malfunction (Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
REAR AXLE -Troubleshooting
ERASING THE DIAGNOSIS CODES
Connect the MUT-IIto the 16-pin diagnosis connector and
erase the diagnosis code. (Refer to GROUP 00 – How to
Use Troubleshooting/Inspection Service Points.)
Caution
Turn the ignition switch to the LOCK (OFF) position before
connecting or disconnecting the MUT-II.
INSPECTION CHART FOR DIAGNOSIS CODE
Diagnosis
code No.Diagnosis itemsReference page
12Power supply voltage (valve power supply) systemopen- or short-circuitRefer to
GROUP22
13Failsafe relay system
GROUP22.
21FR wheel speed sensor systemopen- or short-circuit
22FL wheel speed sensor systemopen- or short-circuit
23RR wheel speed sensor systemopen- or short-circuit
24RL wheel speed sensor systemopen- or short-circuit
25Wrong-diameter tire
26Wheel speed sensor (faulty output signal)
31Steer sensor (ST-1, ST-2, ST-N) systemopen- or short-circuit
32Steer sensor (ST-N) systemshort-circuit
33fixed
34Steer sensor (ST-1, ST-2) systemshort-circuit or output
fixed
41TPS systemopen-circuit or ground
42short-circuit
45Pressure sensor systemopen-circuit or ground
46open earth
47abnormal power supply
51G sensor (longitudinal) systemopen- or short-circuit
52defective sensor
56G sensor (lateral) systemopen- or short-circuit
57defective sensor