MPI – Troubleshooting13-54
INSPECTION PROCEDURE 46
Check fuel pump circuit.
Measure at the fuel pump relay connector D-18.
Disconnect the connector and measure at the harness side.
Continuity between 1 and earth
OK:ContinuityNGCheck the following connector:
D-04NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between fuel pump and earth, and repair
if necessary.
OK
Check the following connectors: A-123, B-64, D-18, D-32NG
Repair OKCheck trouble symptom.
NG
Check the harness wire between fuel pump and fuel pump relay
No.2 connector.NG
Repair
OK
Replace the fuel pump.
INSPECTION PROCEDURE 47
Check the fuel pump drive control circuit.
NG
Check the harness wire between the fuel pump relay and engine-
ECU connector.
OK
Check trouble symptom.
OK
Check trouble symptom.
NG
Check the harness wire
between fuel pump relay
and ignition switch con-
nector.NG
Repair
OK
Check the ignition switch. (Refer to GROUP 54.)OK
Check trouble symptom.
NG
Replace the engine-ECU.
NG
Repair
OK
Check the following connector: B-59
OK
Measure at the engine-ECU connector B-59.
Disconnect the connector and measure at the harness side.
Voltage between 8 and earth (Ignition switch: ON)
OK:System voltageNG
Measure at the fuel pump relay connector B-28.
Disconnect the connector and measure at the harness side.
Voltage between 3, 4 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connectors: B-65, B-76NG
Repair
Check the following
connector: B-28NG
Repair
MPI – TroubleshootingMPI – Troubleshooting13-55
INSPECTION PROCEDURE 48
Check air flow sensor control circuit.
2, 3. NGCheck the following
connector: B-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and air flow sensor con-
nector.NG
Repair
OK
Replace the engine-ECU.
OK
Check trouble symptom.
NG
Replace the air flow sensor.
NG
Repair
OK
Check the following connector: A-25
Measure at the air flow sensor connector A-25.
Disconnect the connector and measure at the harness side.
1. Voltage between 4 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Ignition switch: ON)
OK:4.8–5.2 V
3. Continuity between 5 and earth
OK:Continuity1. NGCheck the harness wire between the air flow sensor and control
relay connector, and repair if necessary.
INSPECTION PROCEDURE 49
Check throttle position sensor output circuit.
Measure at the engine-ECU connector B-62.
Connect the connector.
Voltage between 84 and earth (Ignition switch: ON)
OK:0.3–1.0 V (Throttle valve at idle position)
4.5–5.5 V (Throttle valve fully open)NGCheck the following
connector: B-62NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
OK
Check the harness wire between engine-ECU and throttle position
sensor connector, and repair if necessary.
INSPECTION PROCEDURE 50
Check injector control circuit.
Measure at the engine-ECU connector B-59.
Disconnect the connector and measure at the harness side.
Voltage between 1, 2, 14, 15 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connectors:
A-53, A-54, A-55, A-56NG
Repair
OK
Check trouble symptom.
NG
Check the harness between engine-ECU and injector connector,
and repair if necessary.
OK
Check the following connector: B-59
OK
Check trouble symptom.
NG
Replace the engine-ECU.NG
Repair
MPI – Troubleshooting13-56
DATA LIST REFERENCE TABLE
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
11Oxygen
sensorEngine:After having
warmed up
Air/fuel mixture is
made leaner when de-
When at 4,000 r/min,
engine is suddenly
decelerated200 mV or lessProcedure
No. 3113-42
made leaner when de-
celerating, and is made
richer when racing.
When engine is
suddenly raced600 – 1,000 mV
Engine:After having
warmed up
The oxygen sensor
si
gnal is used to check
Engine is idling400 mV or less
(Changes)
signal is used to check
the air/fuel mixture
ratio, and control
condition is also
checked by the ECU.2,500 r/min600 – 1,000 mV
12Air flow
sensor* Engine coolant
tem
perature: 80 –
Engine is idling17 – 43 Hz––
sensor
95C
Lamps, electric
li f d ll
2,500 r/min46 – 86 Hzp
cooling fan and all
accessories: OFF
Transmission:
Neutral (A/T:
P range)Engine is racedFrequency
increases in
response to
racing
12Air flow
sensor* Engine coolant
tem
perature: 80 –
Engine is idling12 – 38 Hz––
sensor
95C
Lamps, electric
li f d ll
2,500 r/min36 – 76 Hzp
cooling fan and all
accessories: OFF
Transmission:
Neutral (A/T:
P range)Engine is racedFrequency
increases in
response to
racing
13Intake air
temperature
sensor
Ignition switch: ON or
with engine runningWhen intake air
temperature is –20C–20CCode No.
1313-9
sensorWhen intake air
temperature is 0C0C
When intake air
temperature is 20C20C
When intake air
temperature is 40C40C
When intake air
temperature is 80C80C
NOTE
*: In a new vehicle [driven approximately 500 km or less], the air flow sensor output frequency is sometimes
10% higher than the standard frequency.
MPI – Troubleshooting13-57
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
14Throttle
position
Ignition switch: ONSet to idle position300 – 1,000 mVCode No.
14
13-9
position
sensor
Gradually openIncreases in
proportion to
throttle opening
angle
14
Open fully4,500 – 5,500 mV
16Power
supply
voltageIgnition switch: ONSystem voltageProcedure
No. 2413-35
18Cranking
signal Ignition switch: ONEngine: StoppedOFFProcedure
No. 2713-38
g
(ignition
switch-ST)Engine: CrankingON
21Engine
coolant
temperature
sensor
Ignition switch: ON or
with engine runningWhen engine
coolant temperature
is –20C–20CCode No.
2113-10
sensor
When engine
coolant temperature
is 0C0C
When engine
coolant temperature
is 20C20C
When engine
coolant temperature
is 40C40C
When engine
coolant temperature
is 80C80C
MPI – Troubleshooting13-58
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
22Crank angle
sensorEngine: Cranking
Tachometer:
ConnectedCompare the engine
speed readings on
the tachometer and
the MUT-II.Accord––
Engine: Idling
Idle position
switch: ONWhen engine
coolant temperature
is –20C1,300 – 1,500 rpm
When engine
coolant temperature
is 0C1,300 – 1,500 rpm
When engine
coolant temperature
is 20C1,300 – 1,500 rpm
When engine
coolant temperature
is 40C1,150 – 1,350 rpm
When engine
coolant temperature
is 80C750 – 950 rpm
25Barometric
pressure
Ignition switch: ONAt altitude of 0 m101 kPaCode No.
25
13-14
pressure
sensor
At altitude of 600 m95 kPa
25
At altitude of 1,200 m88 kPa
At altitude of 1,800 m81 kPa
26Idle position
switchIgnition switch: ON
Check by operating
accelerator pedal
Throttle valve:
Set to idle positionONProcedure
No. 2613-38
accelerator pedal
repeatedly.)Throttle valve:
Slightly openOFF*
27Power
steering fluid
pressure
Engine: IdlingSteering wheel
stationaryOFFProcedure
No. 2813-39
pressure
switchSteering wheel
turningON
28A/C switchEngine: Idling
(when A/C switch isA/C switch: OFFOFFProcedure
No. 2913-39
(Ctc
ON, A/C compressor
should be operating.)A/C switch: ONON
NOTE
*: The idle position switch normally turns off when the voltage of the throttle position sensor is 50 –
100 mV higher than the voltage at the idle position. If the throttle position switch turns back on
after the throttle valve has opened, the idle position switch and the throttle position sensor need
to be adjusted.
MPI – Troubleshooting13-59
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
41Injectors*1
coolant temperature
is 0C (injection is
carried out for all
cylinders
simultaneously)27 – 41 ms––
When engine
coolant temperature
is 20C14 – 22 ms
When engine
coolant temperature
is 80C3.9 – 5.9 ms
Injectors*2
Engine coolant
temperature:
80–95C
Engine is idling1.2 – 2.4 ms
TION-IV>80–95C
Lamps, electric
cooling fan and all
accessories: OFF
2,500 r/min1.0 – 2.2 ms
accessories: OFF
Transmission:
Neutral (A/T :
P range)When engine is
suddenly racedIncreases
41Injectors*1
coolant temperature
is 0C27 – 40 ms––
When engine
coolant temperature
is 20C14.5 – 21.7 ms
When engine
coolant temperature
is 80C3.8 – 5.6 ms
Injectors*2
Engine coolant
temperature:
80–95C
Engine is idling0.9 – 2.1 ms
TION-V, VI>80–95C
Lamps, electric
cooling fan and all
accessories: OFF
2,500 r/min0.7 – 1.9 ms
accessories: OFF
Transmission:
Neutral (A/T :
P range)When engine is
suddenly racedIncreases
NOTE
*1: The injector drive time represents the time when the cranking speed is at 250 r/min or below when
the power supply voltage is 11 V.
*
2: In a new vehicle [driven approximately 500 km or less], the injector drive time is sometimes 10%
longer than the standard time.
MPI – Troubleshooting13-60
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
44Ignition coils
and power
transistors
Timing lamp is set.
(The timing lampEngine is idling3ATDC –
13BTDC––
TION-IV>
(tgp
is set in order to
check actual
ignition timing.)2,500 r/min24 – 44BTDC
44Ignition coils
and power
transistors
Engine: After
having warmed up
Timing lamp is set
Engine is idling0 – 13BTDC––
transistors
2,500 r/min24 – 44BTDC
45ISC
(stepper)
motor
position *
Engine coolant
temperature: 80 –
90C
Lam
ps, electric
A/C switch: OFF2 – 25 steps––
position Lamps, electric
cooling fan and all
accessories: OFF
Transmission:
Neutral (A/T :
P range)
Idl iti
A/C switch:
OFF → ONIncreases by
10 – 70 steps
g)
Idle position
switch: ON
Engine: Idling
When A/C switch
is ON, A/C
compressor should
be operatingA/C switch: OFF
Select lever:
N range →
D rangeIncreases by
5 – 50 steps
49A/C relayEngine: After having
warmed up/Engine is
idlingA/C switch: OFFOFF (Compressor
clutch is not
operating)Procedure
No. 2913-39
A/C switch: ONON (Compressor
clutch is
operating)
NOTE
*: In a new vehicle [driven approximately 500 km or less], the stepper motor has sometimes 30 steps
greater than the standard value.
Caution
When shifting the select lever to D range, the brakes should be applied so that the vehicle does
not move forward.
MPI – Troubleshooting13-61
8. ACTUATOR TEST REFERENCE TABLE
Item
No.Inspection
itemDrive contentsInspection contentsNormal conditionInspection
procedure
No.Reference
page
01InjectorsCut fuel to No.
1 injectorEngine:
After having warmed
up/Engine is idling
Idling condition
becomes different
(becomes unsta
Code No.
4113-15
02Cut fuel to No.
2 injectorup/Engine is idling
(Cut the fuel supply to each
injector in turn and check
li d hi h d’ff
(becomes unsta-
ble, resulting in
engine stall).
03Cut fuel to No.
3 injector
j
cylinders which don’t affect
idling.)
04Cut fuel to No.
4 injector
07Fuel pumpFuel pump
operates and
fuel is recircu-
lated.Engine:
Cranking
Fuel
pump:
Forced
driving
Inspect ac-
cording to
Pinch the
return hose
with fingers
to feel the
pulse of the
fuel being
recirculated.Pulse is felt.Procedure
No. 2513-36
cording to
both the
above condi-
tions.
Listen near
the fuel tank
for the
sound of
fuel pump
operation.Sound of opera-
tion is heard.
09Fuel
pressure
control
valveSolenoid valve
turns from
OFF to ON.Ignition switch: ONSound of opera-
tion can be heard
when solenoid
valve is driven.Procedure
No. 3413-45
12Waste
gate
solenoid
valveSolenoid valve
turns from
OFF to ON.Ignition switch: ONSound of opera-
tion can be heard
when solenoid
valve is driven.Procedure
No. 3513-45
13Fuel pump
relay No.2Turn fuel
pump relay
No.2 from
OFF to ON.Ignition switch: ON
Listen to pump operation
sound near fuel tank.Sound of opera-
tion can be heard.Procedure
No. 2513-36
17Basic igni-
tion timingSet to ignition
timing adjust-
ment modeEngine: Idling
Timing light is set5BTDC––