Mitsubishi FUEL Manual page 280

13I-86
INSPECTION PROCEDURE 20
Idling speed is improper when A/C is operating
If the engine-ECU <M/T> or engine-A/T-ECU <A/T> detects that the air conditioner
is on, it activates the idle speed control (ISC) servo to control idle-up operation.
The A/C pressure sensor monitors the A/C compressor, and sends a signal to the
engine-ECU<M/T> or engine-A/T-ECU<A/T>. The ECU controls fast idling speed
according to this signal.
Measure at the A/C pressure sensor
connector A-52.
D Disconnect the connector, and
measure at the harness side.
(1) Voltagebetween3andearth(Ignition
switch: ON)
OK: 4.5 - 5.5 V
(2) Continuity between 1 and earth
OK: Continuity
OK
Measure at the engine-ECU connector
C-164 <M/T> or engine-A/T-ECU con-
nector C-175 <A/T>.
D Connect the connector.
D Voltage between 64 <M/T> or 94
<A/T> and earth
(Engine: Idling)
OK: 8 V or more [When the A/C
is MAX. COOL condition
(when the load by A/C is high)]
4 V or lower [When the A/C
is MAX. HOT condition (when
the load by A/C is low)]
INSPECTION PROCEDURE 21
Fans (radiator fan, A/C condenser fan) are inoperative.
The engine-ECU <M/T> or engine-A/T-ECU <A/T> sends a duty signal to the fan
controller according to engine coolant temperature, vehicle speed, or A/C switch load.
The fan controller controls radiator fan and condenser fan speeds, based on this
signal. (The closer the terminal voltage comes to 5 V, the higher the fan speedbecomes.)
Measure at engine-ECU connector C-163 <M/T> or engine-A/T-
ECU connector C-175 <A/T>.
D Disconnect the connector, measure at the harness side.
D Voltage between terminal 18 and earth (Ignition switch: ON)
OK: 4.8 - 5.2 V (The fan runs at high speed.)
D Earth terminal 18. (Ignition switch: ON)
OK: The fan stops.
Check the following connectors: C-163 <M/T>, C-175 <A/T>
OK
Check trouble symptom.
MUT-II Data list
21 Engine coolant temperature sensor
OK: After the engine has been warmed up, the engine coolant
temperature during idling is identical to the MUT-II reading.
Check the thermostat.
Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.
GDI - GDI -
(1) NG
Check the following connectors:
C-14 <L.H.>, (C-47, C-115) <R.H.>,
C-81, C-164 <M/T>, C-175 <A/T>
Check the trouble symptoms.
(2) NG
Check the following connectors:
C-14 <L.H.>, C-115 <R.H.>, C-81,
C-163 <M/T>, C-177 <A/T>
NG
Check the trouble symptoms.
Check the following connectors:
A-52, C-14 <L.H.>, C-115 <R.H.>,
C-81, C-164 <M/T>, C-175 <A/T>
Check the trouble symptoms.
OK
Replace the engine-ECU<M/T> or
engine-A/T-ECU <A/T>.
OK
NG
Repair
NG
OK
OK
Troubleshooting Troubleshooting
Probable cause
D Malfunction of the A/C control system
D Improper
short-circuited harness wire
D Malfunction of the A/C pressure sensor
D Malfunction of the engine-ECU <M/T>
D Malfunction of the engine-A/T-ECU <A/T>
NG
OK
NG
NG
Repair
OK
NG
NG
Repair
OK
NG
Replace the A/C pressure sensor.
Probable cause
D Malfunction of the fan motor relay
D Malfunction of the fan motor
D Malfunction of the fan controller
D Open or short circuit, or poor connector contact
D Malfunction of the engine-ECU <M/T>
D Malfunction of the engine-A/T-ECU <A/T>
NG
Checkthefollowingconnectors:A-22,B-30,C-163<M/T>, C-175
<A/T>
OK
Check trouble symptom.
NG
Check the harness wire between the engine-ECU <M/T> or engine-
A/T-ECU <A/T> and fan controller.
OK
Check the radiator fan and condenser fan circuit. (Refer to GROUP
14 - Troubleshooting.)
NG
Check the engine coolant temperature sensor system. (Refer to
P.13I-18, INSPECTION PROCEDURE FOR DIAGNOSIS CODE
P0115.)
NG
Replace
connector contact, open
Repair
Check the harnesswire between the A/C pressure
sensor and engine-ECU <M/T> or engine-A/T-
ECU <A/T>.
NG
OK
Repair
Replace the engine-ECU<M/T> or engine-A/T-
ECU <A/T>.
Check the harnesswire between the A/C pressure
sensor and engine-ECU <M/T> or engine-A/T-
ECU <A/T>, and repair if necessary.
Check the harnesswire between the A/C pressure
sensor and the engine-ECU <M/T> orengine-A/T-
ECU <A/T>.
OK
Repair
NG
NG
Repair
circuit or
Repair