Page 461 of 1216

FUEL SYSTEM - Troubleshooting14-7
Symptom
Engine will not startor start too hard(Cranks OK)
Rough idle or engine
stumbles
Trouble in the MPI systemCheck for output of self-diagnosis
code.Read the code with a voltmeter.Malfunction
of the fuel pump drive control systemCheck the fuel pump drive controlsystem
and the fuel pump.Malfunction
of the ignition timing control systemMalfunction
of the power transistor
Check the ignition timing.
Check the power transistor as a single
unit.
Power is not supplied to the engine control unit.Check the power supply circuit.Malfunction
of the control relayMalfunction
of the injector
Replace.
Check the injector drive circuit.
Check the injector as a single unit.
The fuel pressure is not proper.Check the fuel pressure.
I
Vacuum hose disconnected or damagedRepair or replace.IMalfunction of
the engine control unit) Replace.
Wire breakage or short circuit occurs in theRepair or replace.
harness, or the connector is improperly connected.
Trouble in the MPI systemCheck for output of self-diagnosis
code.Read the code with a voltmeter.Malfunction
of the sensor
l Intake air temperature sensor
Check the sensor-related circuit.
Check the sensor as a single unit
Probable causeRemedy
l Engine coolant temperature sensorl Barometric pressure sensor
l Ignition switchl Idle position switchl Throttle position sensorl No. 1 cylinder TDC sensor, crank angle sensor
l TDC sensor, crank angle sensor<2.0L DOHC Engine>
l Power steering oil pressure switch
l Air conditioner switch
l Inhibitor switch l Motor position sensor <1.8L Engine>l Air flow sensor0 Oxygen sensorMalfunction of the engine control system
l
Stepper motor <2.0L DOHC Engine>l Injector0 Power transistor
Check the actuator-related circuit.Check the actuator as a single unit.
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Page 463 of 1216
Page 515 of 1216

FUEL SYSTEM - MPI System Inspection <1.8L Engine>
outputDiagnosis code
referenceDiagnosis itemCheck item (Remedy)
orderOutput signal patternNo.Memory
7Engine coolantRetainedl Harness and connectortemperature sensor
:-rlrLn- 2’
l Engine coolant temper-
ature sensor
12A0107
8Crank angle sensor
:nn 22
Retainedl Harness and connector
(If harness and connector
are normal, replacedistributor assembly.)
12A0107
9No. 1 cylinder top
dead center sensorH
Lnn 23
Retainedl Harness and connector
(If harness and connector
are normal, replacedistributor assembly.)
12A0107
10Vehicle speed sensor24Retainedl Harness and connector
(reed switch)H
Lu 1 nnJln
l Vehicle speed sensor
(reed switch)
12A0107
11Barometric pressure25Retainedl Harness and connector
sensorH
u I nl-uvln
(If harness and connector
are normal, replace
Lbarometric pressure
12A0107sensor assembly.)
12Ignition timing adjust-36-l Harness and connectorment signalH
LUUI nluvuuL
12R0468
13Injector
:m 41
Retainedl Harness and connector0 Injector coil resistance
12A0105
14Fuel pump42Retainedl Harness and connectorH0 Control relay
LUUUI nn
12A0105
15EGR 43Retainedl Harness and connectorl EGR temperature sensor
H
u u u u-inn
l EGRvalvel EGR valve control sole-Lnoid valve
12A0105l EGR valve control vacuurr
16Normal state---H
Ln
12A0104
NOTEReplace the engine control unit if a malfunction code is output although the inspection reveals that there is no problem with the check
items.
Page 519 of 1216

FUEL SYSTEM - MPI Svstem InsDection <1.8L Engine>14-65
3FUO349
/--
’ 3FU03991
Idle speed controlservo connector(motor side, front view)
3FUO393
INHIBITOR SWITCHN14QRACsRefer to GROUP 21
- Service Adjustment Procedures.
POWER STEERING OIL PRESSURE SWITCH
N14flCJBRefer to GROUP 19 for power steering system inspection.
INJECTORSN14QTAGCHECKING OPERATION SOUND
Using a sound-scope, check the operation sound (“chi-chi-chi”)of injectors during idling or during cranking.
Check that as the rotating speed increases, the frequency of
the operating sound also increases.
Caution
Note that even if the injector you are checking is not
operating, you will hear the operating sound of the other
injectors.
NOTEIf no operating sound is heard from the injector that is being
checked, check the injector drive circuit. If there is nothing
wrong with the circuit, a defective injector or engine control
unit is suspected.
MEASURING RESISTANCE BETWEEN TERMINALS
(1) Remove the injector connector.
(2) Measure the resistance between the terminals.
Standard value: 13
- 16 L(Z [at 20°C (68”F)I(3) Install the injector connector.
IDLE SPEED CONTROL SERVO
INSPECTION
NlQQUAAb(1) Disconnect the idle speed control servo connector.
(2) Check continuity of the idle speed control servo coil.
IMeasuring terminalsIContinuityI
@ - @ Conductive5 to 35 fi resistance
at 20°C (68°F)
Page 529 of 1216

FUEL SYSTEM - MPI Svstem InsDection <2.0L DOHC Engine>
outputDiagnosis codeIreferenceDragnosrs ItemCheck item (Remedy)orderOutput signal patternNo.Memory
7Crank angle sensor
:nn **
Retainedl Harness and connector
(If harness and connector
are normal, replace crank
angle sensor assembly.)
12A0107
8Top dead center
:- 23
Retainedl Harness and connectorsensor (No.1 and(If harness and connector
No. 4 cylinder)are normal, replace crank
angle sensor assembly.)
12A0107
9Vehicle speed sensor24Retainedl Harness and connector
(reed swatch)H
I u I nlvln
l Vehicle speed sensor
(reed switch)
L12A0107
10Barometnc pressure25Retainedl Harness and connector
sensorH(If harness and connector
are normal, replace
LULllnMllbarometric pressure
12A0107sensor assembly.)
11Detonation sensorRetainedl Harness and connector
:m 31
l Detonation sensor
12R0468
12Injector
:m 41
Retainedl Harness and connector0 Injector coil resistance
12A0105
13Fuel pump42Retainedl Harness and connectorH
UUUI nn
0 Control relay
L12A0105
14EGR 43Retainedl Harness and connector
Hl EGR temperature sensor
u u u I nnn
l EGRvalvel EGR valve control sole-Lnoid valve
12A0105l EGR valve control vacuum
15Ignition coil44Retainedl Harness and connectorH
UUUL-llMlL
0 Ignition coil0 Power transistor
L12A0105
16Normal state---H
L
12A0104
NOTEReplace the engine control unit if a malfunction code is output although the inspection reveals that there is no problem with the check
items.
Page 533 of 1216

FUEL SYSTEM - MPI System Inspection <2.0L QOHC Engine>14-79EGR TEMPERATURE SENSOR
N14RCHAaRefer to GROUP 25
- Exhaust Gas Recirculation System.
VEHICLE SPEED SENSOR
Refer to GROUP 8
- Meters and Gauges.
N140EBBaAIR CONDITIONER SWITCH
Nl4QQAEaRefer to GROUP 8
- Column Switch.
POWER STEERING OIL PRESSURE SWITCH
N14RCJBRefer to GROUP 19 for power steering system inspection.
INJECTORS
NWXAHCHECKING OPERATION SOUND
Using a sound-scope, check the operation sound (“chi-chi-chi”)of the injectors during idling or during cranking.
Check to be sure that the operation sound increases when the
engine speed is increased.
Caution
Note that the sounds of other injectors may be heard even
though the injector being checked is not operating, so caremust be taken when checking.
NOTEIf the operation sounds cannot be heard, check the injector
activation circuit.
If this circuit is normal, there is probably a malfunction of the
injector or of the engine control unit.
MEASURING OF RESISTANCE BETWEEN TERMINALS
(1) Disconnect the connector for the injectors.
(2) Measure the resistance between terminals.
Standard value:
13
-16 S2 [at 20°C (68”F)]2
- 3 52 [at 20% (68”F)]
(3) Connect the connector for the injectors.
IDLE SPEED CONTROL SERVO
N14QUADCHECKING OPERATING SOUND
(1) Check that when the ignition switch is placed in the ON
position (the engine not started), the operating sound of thestepper motor can be heard over the idle speed control
servo.
(2) If no operating sound can be heard, check the stepper
motor drive circuit.
(If the circuit is good, a defective stepper motor or engine
control unit is suspected.)
Page 534 of 1216

14-80FUEL SYSTEM - MPI System Inspection <2.0L DOHC Enginh
7FUOOlO6FU1426
7FUOOllCHECKING COIL RESISTANCE
(1) Disconnect the idle speed control servo connector.
(2) Measure the resistance between terminals
@ and @ or
between terminals @and @ of the idle speed control servo
connector.Standard resistance: 28
- 33 fl [at 20°C (68”F)l(3) Measure the resistance between terminals
@ and @ or
between terminals @ and @ of the idle speed control servo
connector.Standard resistance: 28
- 33 LR [at 20°C (68”F)]OPERATION CHECK
(1) Remove the throttle body.
(2) Remove the stepper motor.
(3) Apply voltage as indicated below and check for presence/
absence of vibration due to stepper motor operation.
1. Connect the positive terminal of the power supply
(about
6V) to terminals @ and @ of the connector.
2. Connect the negative terminal of the power supply to
terminals @ and
@.3. Connect the negativeterminal to terminals
@ and @.
4.Connect the negative terminal to terminals @ and @.
5.Connect the negative terminal to terminals @ and @.6. Connect the negative terminal to terminals
@ and @.7. Connect the terminals in sequence from step 6 to 2.
(4) If vibration is felt as a result of the inspections, the stepper
motor can be judged as normal.