CIRCUIT DIAGRAMSB-71
MULTI-PURPOSE FUSE (In junction block)
Power supply
circuitNo.Rated
capacity (A)Identification
colourCircuit
Ignition
switch
IG1110RedIgnition coil
switch
27.5BrownColumn switch, combination meter, ETACS-ECU,
SRS-ECU, vehicle speed sensor and ACD mode
changeover switch
37.5BrownETACS-ECU and SRS-ECU
4---
IG257.5BrownA/C compressor relay, A/C-ECU, blower relay,
condenser fan relay, defogger relay, front-ECU,
4WD-ECU, steering wheel sensor and inter cooler
water splay relay
Multi-purpose fuse
No. 20 (Defogger
relay)6---
Ignition
switch
ACC720YellowFront-ECU and windshield wiper motor
switch
IG187.5BrownEngine-ECU and fuel pump relay (1) and fuel pump
relay (2)
ACC915BlueCigarette lighter
10---
117.5BrownA/C-ECU and remote controlled mirror switch
IG2127.5BrownABS-ECU, G-sensor (longitudinal) and G-sensor
(lateral)
ACC13---
14---
Fusible link No. 1
Battery/alternator
1515BlueDiagnosis connector
Battery/alternator
1610RedRear fog lamp relay
1710RedETACS-ECU
18---
1930GreenBlower motor and resistor
2030GreenDefogger
ENGINE -On-vehicle ServiceENGINE -On-vehicle Service11A-10
Standard value: 5_BTDC±3_
5. Run the engine at idle for 2 minutes.
6. Check the idle speed. Select item No. 22 and take a
reading of the idle speed.
Curb idle speed: 850±100 r/min
NOTE
The idle speed is controlled automatically by the idle speed
control (ISC) system.
7. If the idle speed is outside the standard value, check
the MPI components by referring to GROUP 13A -
Troubleshooting.
8. Remove the timing light.
9. Turn the ignition switch to the “LOCK” (OFF) position
and then remove the MUT-II.
IDLE MIXTURE CHECK
1. Before inspection, set the vehicle to the pre-inspection
condition.
2. Turn the ignition switch to the “LOCK” (OFF) position,
and then connect the MUT-IIto the diagnosis connector.
3. Set the timing light.
4. Check that the basic ignition timing is within the standard
value.
Standard value: 5_BTDC±3_
5. Run the engine at 2,500 r/min for 2 minutes.
6. Set the CO, HC tester.
7. Check the CO contents and the HC contents at idle.
Standard value
CO contents: 0.1% or less
HC contents: 100 ppm or less
8. If there is a deviation from the standard value, check the
following items:
DDiagnosis output
DClosed-loop control (When the closed-loop control
is normal, the output signal of the oxygen sensor
changes between 0 - 400 mV and 600 - 1,000 mV
at idle.)
DFuel pressure
DInjector
DIgnition coil, spark plug cable, spark plug
DEvaporative emission control system
DCompression pressure
NOTE
Replace the three way catalyst when the CO and HC
contents are not within the standard value, even though
the result of the inspection is normal on all items.
9. Remove the timing light.
MUT-II
ENGINE -On-vehicle Service11A-12
12. Install the ignition coils and spark plugs.
13. Use the MUT-IIto erase the self-diagnosis codes or
disconnect the battery cable from the battery ( - ) terminal
for 10 seconds or more and then reconnect the cable.
NOTE
This will erase the diagnosis code resulting from the crank
angle sensor connector being disconnected.
MANIFOLD VACUUM CHECK
1. Set the vehicle to the pre-inspection condition.
2. Turn the ignition switch to the “LOCK” (OFF) position.
3. Set the engine tachometer or connect the MUT-II.
4. Check that the idle speed is within the standard value.
NOTE
When using the MUT-II, select the code No.22.
5. Connect the three-way union joint to the vacuum hose
between the fuel pressure control valve and the air intake
plenum, and connect a vacuum gauge.
6. Check the manifold vacuum at idle.
Limit: 58 kPa
7. Turn the ignition switch to the “LOCK” (OFF) position.
8. Remove the vacuum gauge and install the vacuum hose
in its original location.
9. Remove the engine tachometer or the MUT-II.
LASH ADJUSTER CHECK
If an abnormal noise (knocking) that seems to be coming
from the lash adjuster is heard after starting the engine and
does not stop, carry out the following check.
NOTE
(1) The abnormal noise which is caused by a problem
with the lash adjusters is generated after the engine
is started, and will vary according to the engine speed.
However, this noise is not related to the actual engine
load.
Because of this, if the noise does not occur
immediately after the engine is started, if it does not
change in accordance with the engine speed, or if
it changes in accordance with the engine load, the
source of the noise is not the lash adjusters.
Vacuum gauge
Fuel pressure
control valve
ENGINE -On-vehicle Service11A-13
(2) If there is a problem with the lash adjusters, the noise
will almost never disappear, even if the engine has
been run at idle to let it warm up.
The only case where the noise might disappear is
if the oil in the engine has not been looked after
properly and oil sludge has caused the lash adjusters
to stick.
1. Start the engine.
2. Check that the noise occurs immediately after the engine
is started, and that the noise changes in accordance
with changes in the engine speed.
If the noise does not occur immediately after the engine
is started, or if it does not change in accordance with
the engine speed, the problem is not being caused by
the lash adjusters, so check for some other cause of
the problem. Moreover, if the noise does not change in
accordance with the engine speed, the cause of the
problem is probably not with the engine. (In these cases,
the lash adjusters are normal.)
3. While the engine is idling, check that the noise level does
not change when the engine load is varied.
If the noise level changes, the cause of the noise is
probably parts striking because of worn crankshaft
bearings or connecting rod bearings. (In such cases, the
lash adjusters are normal.)
4. After the engine has warmed up, run it at idle and check
if any noise can be heard.
If the noise has become smaller or disappeared, oil sludge
could make the lash adjusters stick. Clean the lash
adjusters. (Refer to the Engine Workshop Manual.) If not
improved, go to step 5.
5. Bleed air from the lash adjusters.
6. If the noise has not disappeared even after the air
bleeding, clean the lash adjusters.
(Refer to GROUP 11B - Rocker Arms and Camshaft.)
NOTE
(1) If the vehicle is parked on a slope for a long period
of time, the amount of oil inside the lash adjuster
will decrease, and air may get into the high pressure
chamber when starting the engine.
(2) After parking the vehicle for long periods, the oil drains
out of the oil passage, and it takes time for the oil
to be supplied to the lash adjuster, so air can get
into the high pressure chamber.
(3) If either of the above situations occur, the abnormal
noise can be eliminated by bleeding the air from inside
the lash adjusters.
ENGINE -On-vehicle Service11A-14
1. Check the engine oil and replenish or replace the oil
if necessary.
NOTE
(1) If there is a only small amount of oil, air will be drawn
in through the oil screen and will get into the oil
passage.
(2) If the amount of oil is greater than normal, then the
oil will being mixed by the crankshaft and a large
amount of air may get mixed into the oil.
(3) If the oil is degenerated, air and oil will not separate
easily in oil, and the amount of air mixed into the
oil will increase.
(4) If the air which has been mixed in with the oil due
to any of the above reasons gets into the high pressure
chamber of the lash adjuster, the air inside the high
pressure chamber will be compressed when the valve
is open and the lash adjuster will over-compress,
resulting in abnormal noise when the valve closes.
This is the same effect as if the valve clearance is
adjusted to be too large by mistake. If the air inside
the lash adjusters is then released, the operation
of the lash adjusters will return to normal.
2. Run the engine at idle for 1 - 3 minutes to let it warm
up.
3. With no load on the engine, repeat the drive pattern shown
in the illustration at left and check if the abnormal noise
disappears. (The noise should normally disappear after
10 - 30 repetitions, but if there is no change in the noise
level after 30 repetitions or more, the problem is probably
not due to air inside the lash adjusters.)
4. After the noise has disappeared, repeat the drive pattern
shown in the illustration at left a further 5 times.
5. Run the engine at idle for 1 - 3 minutes and check that
the noise has disappeared.
Good
High-pressure chamber
Gradually open the
throttle valve.
Drive pattern for air bleeding
Close the throttle
valve.
Approx.
3,000 r/min
15
seconds15
seconds
Idle speed
Once
MPI -General Information13A-3
GENERAL INFORMATION
The Multipoint Fuel Injection System consists
of sensors which detect the engine conditions,
the engine-ECU which controls the system
based on signals from these sensors, and
actuators which operate under the control of
the engine-ECU. The engine-ECU carries outactivities such as fuel injection control, idle
speed control and ignition timing control. In
addition, the engine-ECU is equipped with
several diagnosis modes which simplify
troubleshooting when a problem develops.
FUEL INJECTION CONTROL
The injector drive times and injector timing are
controlled so that the optimum air/fuel mixture
is supplied to the engine to correspond to the
continually-changing engine operation condi-
tions.
A single injector is mounted at the intake port
of each cylinder. Fuel is sent under pressure
from the fuel tank by the fuel pump, with the
pressure being regulated by the fuel pressure
regulator. The fuel thus regulated is distributed
to each of the injectors.
Fuel injection is normally carried out once for
each cylinder for every two rotations of the
crankshaft. The firing order is 1-3-4-2. This iscalled sequential fuel injection. The
engine-ECU provides a richer air/fuel mixture
by carrying out “open-loop” control when the
engine is cold or operating under high load
conditions in order to maintain engine
performance. In addition, when the engine is
warm or operating under normal conditions,
the engine-ECU controls the air/fuel mixture
by using the oxygen sensor signal to carry out
“closed-loop” control in order to obtain the
theoretical air/fuel mixture ratio that provides
the maximum cleaning performance from the
three way catalyst.
IDLE AIR CONTROL
The idle speed is kept at the optimum speed
by controlling the amount of air that bypasses
the throttle valve in accordance with changes
in idling conditions and engine load during
idling. The engine-ECU drives the idle speed
control motor to keep the engine running at
the pre-set idle target speed in accordance
with the engine coolant temperature and airconditioner load. In addition, when the air
conditioner switch is turned off and on while
the engine is idling, the idle speed control motor
operates to adjust the throttle valve bypass
air amount in accordance with the engine load
conditions in order to avoid fluctuations in the
engine speed.
IGNITION TIMING CONTROL
The power transistor located in the ignition
primary circuit turns ON and OFF to control
the primary current flow to the ignition coil. This
controls the ignition timing in order to provide
the optimum ignition timing with respect to theengine operating conditions. The ignition timing
is determined by the engine-ECU from the
engine speed, intake air volume, engine coolant
temperature and barometric pressure.
SELF-DIAGNOSIS FUNCTION
DWhen an abnormality is detected in one
of the sensors or actuators related to
emission control, the engine warning lamp
(check engine lamp) illuminates as a
warning to the driver.
DWhen an abnormality is detected in one
of the sensors or actuators, a diagnosis
code corresponding to the abnormality is
output.DThe RAM data inside the engine-ECU that
is related to the sensors and actuators can
be read by means of the MUT-II. In addition,
the actuators can be force-driven under
certain circumstances.
MPI -Troubleshooting13A-30
Code No. P0201 No. 1 injector systemProbable cause
Inspection Range
DThe engine speed is 50 - 1,000 r/min.
DThe throttle position sensor output voltage is 1.15 V or less.
DMUT-IIforced drive (actuator test) is not being carried out.
Evaluation Conditions
DSurge voltage at injector coil is not detected for 2 seconds.DNo. 1 injector malfunction
DNo. 1 injector circuit disconnection, short-circuit, or
connector contact defect
DEngine-ECU malfunction
OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
Measure the signal waveform at the
C-126 engine-ECU connector (using
an analyzer).
DEngine: Idling
DVoltage between terminal No. 1 and
earth
OK:The waveform shown on
P.13A-119 (Inspection Proce-
dure Using Analyzer) should
be output.NGReplace the engine-ECU.
OK
Check the harness between the No. 1
injector and engine-ECU.
DCheck for disconnection,
short-circuit and damage of the
output cable.NG
Repair
OK
Check the following connector:
C-126NG
Repair
OK
Check the harness between the resis-
tor (for injector) and engine control
relay.
DCheck for damage of the power
cable.NG
Repair
OK
Check the harness between the No. 1
injector and resistor (for injector).
DCheck for damage of the power
cable.NG
Repair
OK
Check and repair the harness between
the resistor (for injector) and engine
control relay.
DCheck for disconnection and
short-circuit of the power cable.NG
OK
Check the harness between the No. 1
injector and resistor (for injector).
DCheck for disconnection and
short-circuit of the power cable.Repair
OK
Check the resistor. (Refer to
P.13A-138.)
OK
Measure at the B-27 No. 1 injector
connector.
DDisconnect the connector to
measure at the harness side.
DIgnition switch: ON
DVoltage between terminal No. 1 and
earth
OK:System voltageNGCheck the following connectors:
B-11X, B-138, C-108NG
Repair
OK
Measure at the B-27 No. 1 injector
connector.
DDisconnect the connector to
measure at the injector side.
DResistance between terminal No. 1
and terminal No. 2
OK:2-3ΩNGReplace the No. 1 injector.
NG
Check the following connector:
B-27NG
Repair
MUT-IIActuator test
DNo. 01: No. 1 injector
OK:The idling state changes.OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
MPI -Troubleshooting13A-31
Code No. P0202 No. 2 injector systemProbable cause
Inspection Range
DThe engine speed is 50 - 1,000 r/min.
DThe throttle position sensor output voltage is 1.15 V or less.
DMUT-IIforced drive (actuator test) is not being carried out.
Evaluation Conditions
DSurge voltage at injector coil is not detected for 2 seconds.DNo. 2 injector malfunction
DNo. 2 injector circuit disconnection, short-circuit, or
connector contact defect
DEngine-ECU malfunction
OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)
OK
Measure the signal waveform at the
C-126 engine-ECU connector (using
an analyzer).
DEngine: Idling
DVoltage between terminal No. 1 and
earth
OK:The waveform shown on
P.13A-119 (Inspection Proce-
dure Using Analyzer) should
be output.NGReplace the engine-ECU.
OK
Check the harness between the No. 2
injector and engine-ECU.
DCheck for disconnection,
short-circuit and damage of the
output cable.NG
Repair
OK
Check the following connector:
C-126NG
Repair
OK
Check the harness between the resis-
tor (for injector) and engine control
relay.
DCheck for damage of the power
cable.NG
Repair
OK
Check and repair the harness between
the resistor (for injector) and engine
control relay.
DCheck for disconnection and
short-circuit of the power cable.NG
OK
Check the harness between the No. 2
injector and resistor (for injector).
DCheck for disconnection and
short-circuit of the power cable.Repair NG
OK
Check the resistor. (Refer to
P.13A-138.)Repair
OK
Check the harness between the No. 2
injector and resistor (for injector).
DCheck for damage of the power
cable.NG
Repair
OK
Measure at the B-26 No. 2 injector
connector.
DDisconnect the connector to
measure at the harness side.
DIgnition switch: ON
DVoltage between terminal No. 1 and
earth
OK:System voltageNGCheck the following connectors:
B-11X, B-138, C-108NG
Repair
OK
Measure at the B-26 No. 2 injector
connector.
DDisconnect the connector to
measure at the injector side.
DResistance between terminal No. 1
and terminal No. 2
OK:2-3ΩNGReplace the No. 2 injector.
NG
Check the following connector:
B-26NG
Repair
MUT-IIActuator test
DNo. 02: No. 2 injector
OK:The idling state changes.OKIntermittent malfunction
(Refer to GROUP 00 - Points to Note
for Intermittent Malfunctions.)