MPI -Troubleshooting13A-85
Inspection Procedure 23
Fuel pump system
Probable cause
DThe engine-ECU turns the fuel pump relay ON during cranking and engine
operation, and supplies the drive power to the fuel pump.
DWhen operating with a low load, the engine-ECU supplies power to the fuel
pump via the resistor. When operating with a high load, power is directly
supplied and the fuel pump fuel discharge amount is increased.DFuel pump relay 1 malfunction
DFuel pump relay 2 malfunction
DFuel pump relay 3 malfunction
DFuel pump resistor malfunction
DFuel pump malfunction
DFuel pump circuit disconnection, short-circuit, or
connector contact defect
DEngine-ECU malfunction
NG
Intermittent malfunction (Refer to
GROUP 00 - Points to Note for
Intermittent Malfunctions.)OKMUT-IIActuator Test
No. 07: Fuel pump
(Refer to P.13A-107.)
NGMUT-IIActuator Test
No. 13: Fuel pump relay 3
(Refer to P.13A-107.)OK
NG
Replace the fuel pump relay 3.NG
NG
Repair
Check the fuel pump relay 1, fuel
pump relay 2 and fuel pump registor.
(Refer to P.13A-132.)
OK
Measure at the B-140 fuel pump
relay 3.
DDisconnect the connector to
measure at the harness side.
DVoltage between terminal No. 2,
terminal No. 4 and earth
(Ignition switch: ON)
OK:System voltageNG
OK
Check the fuel pump relay 3.
(Refer to P.13A-132.)
OK
Check and repair the harness
between the fuel pump resistor and
fuel pump relay 3. OK
NG
Repair OK
NG
Check the trouble symptoms.
RepairOK
Check the harness between the fuel
pump relay 3 and fuel pump resistor.
Replace the engine-ECU.
Check and repair the harness
between the fuel pump relay 3 and
engine-ECU.
Check the following connector:C-122Measure at the C-122 engine-ECU
connector.
DDisconnect the connector to
measure at the harness side.
DDisconnect the C-126
engine-ECU connector, and earth
the terminal No. 22.
DVoltage between terminal No. 126
and earth
(Ignition switch: ON)
OK:System voltageNG
OK
Check the following connectors:
C-209, C-135(1) NG
Repair NG
NG
Check the trouble symptoms.
Check and repair the harness
between the fuel pump relay 1 and
battery.
(2) NGNG
OK
Check the following connector:
C-210Repair
NGCheck the trouble symptoms.
OK
Check the following connectors:
C-223, C-08
C-102
NG
Repair
NG
Check and repair the harness
between the fuel pump relay 1 and
body earth.
Check the trouble symptoms.OK
To the next page
Measure at the C-223 fuel pump
relay 1.
DDisconnect the connector to
measure at the harness side.
(1) Voltage between terminal No. 3
and earth
OK:System voltage
(2) Voltage between terminal No. 1
and earth
(Ignition switch: ON)
OK:Battery voltage
(2) Resistance between terminal No.
4 and earth
OK:2Ωor less
Repair OK
Check the ignition switch. (Refer to
GROUP 54 - Ignition Switch.)
Check the harness between the fuel
pump relay 1 and ignition switch.
NG
MPI -Troubleshooting13A-87
Inspection Procedure 24
Radiator fan control relay system
Probable cause
When the engine control relay turns ON, the radiator fan control relay turns ON
simultaneously, and power is supplied to the fan controller.
The radiator fan motor is driven when the fan motor drive signal is input to the
fan controller from the engine-ECU.DRadiator fan control relay malfunction
DFan controller malfunction
DRadiator fan motor malfunction
DEngine-ECU malfunction
OK
(1) NG
OK
DCheck the radiator fan control relay. (Refer to GROUP 14
- On-vehicle Service.)NGReplace the radiator fan control relay.
Check the following connector:A-09XNG
Repair
OK
OK
(2) NGCheck the following connectors:
C-136
OK
Check and repair the harness
between the radiator fan control relay
and body earth.
DCheck for disconnection and
damage of the earth cable.
Repair
OK
Check the following connector:A-21
Check and repair the harness
between the radiator fan control relay
and engine control relay.
DCheck for disconnection and
short-circuit of the power cable.
(3) NGCheck and repair the harness
between the battery and radiator fan
control relay.
DCheck for disconnection and
short-circuit of the power cable.
Measure at the A-09X radiator fan
control relay connector.
DRemove the relay, and measure
at the connector side.
(1) Resistance between terminal No.
3 and earth
OK:2Ωor less
(2) Voltage between terminal No. 1
and earth
(Ignition switch: ON)
OK:System voltage
(3) Voltage between terminal No. 4
and earth
OK:System voltage
NG
Repair
OK
Measure at the A-21 fan controller
connector.
DDisconnect the connector to
measure at the harness side.
DIgnition switch: ON
DVoltage between terminal No. 3
and earth
OK:System voltage
To the next pageNG
OK
Check the harness between the
radiator fan control relay and fan
controller.
DCheck for disconnection and
short-circuit of the output cable.NG
Repair
OK
Check the following connectors:
C-136
Repair
OK
OK
Check the harness between the
radiator fan control relay and engine
control relay.
DCheck for damage of the power
cable.NG
Repair
Check and repair the harness
between the radiator fan control relay
and body earth.
DCheck for damage of the earth
cable.
MPI -Troubleshooting13A-88
NGRepair
NG
Repair NG
From the previous page
OK
OK
Replace the engine-ECU.
NG
MUT-IIActuator Test
DNo. 21: Fan controller
DIgnition switch: ON
OK:Radiator fan motor rotates.
NG
Check the radiator fan motor drive.
DDisconnect the C-126
engine-ECU connector.
DIgnition switch: ON
OK:Radiator fan motor rotates
at a high speed.OK
OK
Check the harness between the
battery and radiator fan control relay.
DCheck for damage of the power
cable.RepairMeasure at the C-126 engine-ECU
connector.
DDisconnect the connector to
measure at the harness side.
DIgnition switch: ON
DVoltage between terminal No. 21
and earth
OK:4.9 - 5.1 VOK
OK
Check the harness between the
radiator fan control relay and fan
controller.
DCheck for damage of the output
cable.
Replace the radiator fan motor and
fan controller assembly.NG
NG
OK
Check the following connector:
C-136
A-13
OK
Replace the radiator fan motor and
fan controller assembly.
Check the harness between the fan
controller and engine-ECU.
DCheck for short-circuit of the
output cable.Repair NG
OK
Check the following connector:C-126
Repair
Intermittent malfunction (Refer to
GROUP 00 - Points to Note for
Intermittent Malfunctions.)
MPI -Troubleshooting13A-89
Inspection Procedure 25
Condenser fan relay system
Probable cause
The condenser fan relay turns ON with the signal from the engine-ECU, and
power is supplied to the condenser fan motor.DCondenser fan relay (HI) malfunction
DCondenser fan relay (LOW) malfunction
DCondenser fan motor malfunction
DCondenser fan circuit disconnection, short-circuit,
or connector contact defect
DEngine-ECU malfunction
OK
Check and repair the harness
between the condenser fan relay
(LOW) and engine-ECU.
DCheck for disconnection and
damage of the power cable.
(2) NG
OK
OK
Check the condenser fan motor.
(Refer to GROUP 14 - Engine
Cooling.)
OK
NG
OK
Check the following connector:
A-06X
OK
MUT-IIActuator Test
DNo. 38: Condenser fan (LOW)
DIgnition switch: ON
OK:Condenser fan motor ro-
tates (low speed).NG
OK
Measure at the C-122 engine-ECU
connector.
DMeasure the engine-ECU terminal
voltage.
DIgnition switch: ON
DVoltage between terminal No. 34
and earth
(Ignition switch: ON)
OK:System voltageRepair
NG
To the next page
NGReplace the condenser fan relay
(LOW).
OK
Check the condenser fan relay
(LOW). (Refer to GROUP 14 -
On-vehicle service.)
(1) NGMeasure at the A-06X condenser fan
relay (LOW) connector.
DRemove the relay, and measure
at the connector side.
(1) Voltage between terminal No. 2
and earth
(Ignition switch: ON)
OK:System voltage
(2) Voltage between terminal No. 4
and earth
OK:System voltage
NG
Repair OK
OK
Check the following connectors:
C-135, C-102, C-209, C-210
Check and repair the harness
between the condenser fan relay
(LOW) and ignition switch.
DCheck for disconnection and
damage of the power cable.
Check the following connectors:
C-122, C-136
A-43
Check the following connector:
C-201
NG
Check the ignition switch. (Refer to
GROUP 54 - Ignition switch.)
Replace the ignition switch.
Check and replace the harness
between the battery and condenser
fan relay (LOW).
DCheck for disconnection and
damage of the power cable.
MPI -Troubleshooting13A-90
(2) NG
OK
OK
OK
NG
OK
Check the following connector:
A-07X
OK
MUT-IIActuator Test
DNo. 37: Condenser fan (HI)
DIgnition switch: ON
OK:Condenser fan motor ro-
tates (high speed).NG
Repair
NGReplace the condenser fan relay
(HI).
OK
Check the condenser fan relay (HI).
(Refer to GROUP 14 - On-vehicle
service.)
(1) NGMeasure at the A-07X condenser fan
relay (HI) connector.
DRemove the relay, and measure
at the connector side.
(1) Voltage between terminal No. 2
and earth
(Ignition switch: ON)
OK:System voltage
(2) Voltage between terminal No. 4
and earth
OK:System voltage
NG
Repair OK
OK
Check the following connectors:
C-135, C-102, C-209, C-210
Check and repair the harness
between the condenser fan relay
(HI) and ignition switch.
DCheck for disconnection and
damage of the power cable.
Check the following connector:
C-201
NG
Check the ignition switch. (Refer to
GROUP 54 - Ignition switch.)
Replace the ignition switch.
Check and replace the harness
between the battery and condenser
fan relay (HI).
DCheck for disconnection and
damage of the power cable.
NGCheck the following connector:A-45
OK
Replace the engine-ECU.
OK
To the next page
NG
OK
Check the harness between the
condenser fan relay (LOW) and
engine-ECU.
DCheck for damage of the power
cable.Repair Repair
NGOK
Measure at the A-45 condenser fan
motor connector.
DDisconnect the connector to
measure at the harness side.
DDisconnect the C-122
engine-ECU connector, and earth
the terminal No. 34.
DIgnition switch: ON
DVoltage between terminal No. 2
and earth
OK:System voltageCheck and repair the harness
between the condenser fan relay
(LOW) and engine-ECU.
DCheck for disconnection of the
power cable.
From the previous page
MPI -Troubleshooting13A-93
Inspection Procedure 27
A/C compressor relay system
Probable cause
When the A/C switch ON signal is input to the engine-ECU, the engine-ECU
turns the A/C compressor relay ON.
The A/C compressor magnetic clutch starts with this.DA/C compressor relay malfunction
DA/C compressor magnetic clutch malfunction
DEngine-ECU malfunction
OK
(2) NGCheck the following connector:
C-136
Check and repair the harness
between the battery and A/C
compressor relay.
DCheck for disconnection and
short-circuit of the power cable.
OK
Check the A/C compressor relay. (Refer to 55 - On-vehicle
service.)NGReplace the A/C compressor relay.
Check the following connector:B-12XNG
Repair
OK
OK
Measure at the B-12X A/C
compressor relay connector.
DRemove the relay, and measure
at the connector side.
(1) Voltage between terminal No. 2
and earth
(Ignition switch: ON)
OK:System voltage
(2) Voltage between terminal No. 1
and earth
OK:System voltage(1) NGCheck the following connectors:
C-128
C-210, C-201NG
OK
Check and repair the harness
between the ignition switch and A/C
compressor relay.
DCheck for disconnection and
short-circuit of the power cable.Repair
OKNG
Measure at the A-47 A/C
compressor connector.
DMeasure the engine-ECU terminal
voltage.
DRemove the B-12X A/C
compressor relay, and
short-circuit between the harness
connector’s terminal No. 1 and
terminal No. 4.
DIgnition switch: ON
DVoltage between terminal No. 1
and earth
OK:System voltage
To the next pageRepair
NG
OK
Check the following connector:A-47
Repair
OK
Check the following connector:
C-136
Check and repair the harness
between the A/C compressor relay
and A/C compressor.
DCheck for disconnection and
short - circuit of the output cable.Repair
MPI -Troubleshooting13A-94
OK
OK
Check the harness between the battery and A/C compressor
relay.
DCheck for damage of the power cable.NG
Repair
OK
Check the following connector:C-136
A-43
Repair
NG
Replace the engine-ECU.
NG
Repair
OK
OKMUT-IIData list
DNo. 49: A/C relay
DEngine: Idling
DA/C setting temperature
When room temperature is 25_
or more: Max Cool
When room temperature is 25_
or less: Max Hot
DA/C switch: ON
OK:ON
DA/C switch: OFF
OK:OFF
OK
OK
Measure at the C-126 engine-ECU
connector.
DMeasure the engine-ECU terminal
voltage.
DIgnition switch: ON
DVoltage between terminal No. 8
and earth
OK:System voltageNGCheck the following connector:C-126NG
OK
Check the harness between the A/C
compressor relay and engine-ECU.
DCheck for disconnection and
damage of the earth cable.Repair
OK
Check the harness between the ignition switch and A/C
compressor relay.
DCheck for damage of the power cable.NG
Check the following connectors:C-128
C-130
From the previous page
Intermittent malfunction (Refer to
GROUP 00 - Points to Note for
Intermittent Malfunctions.)
Repair NG
OK
Check the harness between the A/C compressor relay and
engine-ECU.
DCheck for damage of the earth cable.NG
Repair
OK
Check the harness between the A/C compressor relay and
A/C compressor.
DCheck for damage of the output cable.NG
Repair
Replace the A/C compressor magnetic clutch.
MPI -Troubleshooting13A-103
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
14Throttle
position
Ignition switch: “ON”Set to idle position535 - 735 mVCode No.
P0120
13A-21
position
sensor
Gradually openIncreases in pro-
portion to throttle
opening angle
P0120
Open fully4,500 - 5,000 mV
16Battery
voltageIgnition switch: “ON”System voltageProcedure
No. 2213A-82
18Cranking
signalIgnition switch: “ON”Engine: StoppedOFFProcedure
No.2213A-82
signal
(ignition
switch-ST)Engine: CrankingON
No.22
21Engine
coolant
temperature
Ignition switch: “ON”
or engine runningWhen engine coolant
temperature is - 20_C-20_CCode No.
P011513A-19
temperature
sensorWhen engine coolant
temperature is 0_C0_C
When engine coolant
temperature is 20_C20_C
When engine coolant
temperature is 40_C40_C
When engine coolant
temperature is 80_C80_C
22Crank
angle
sensorDEngine: Cranking
DTachometer:
ConnectedCompare the engine
speed readings on the
tachometer and the
MUT-II.Accord--
DEngine: Idle
operationWhen engine coolant
temperature is - 20_C1,300 - 1,500
r/min
When engine coolant
temperature is 0_C1,300 - 1,500
r/min
When engine coolant
temperature is 20_C1,300 - 1,500
r/min
When engine coolant
temperature is 40_C1,150 - 1,350
r/min
When engine coolant
temperature is 80_C600 - 900 r/min
24LVehicle
speed
sensorDrive at 40 km/hApproximately 40
km/hCode No.
P050013A-43