Mitsubishi Galant. Manual — part 309
MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-461
INSPECTION PROCEDURE 27: Incorrect Idle Speed When the A/C is Operating (A/C Switch 2 Signal)
CIRCUIT OPERATION
•
The PCM increases the engine idle speed by
driving the IAC motor when the automatic
compressor-ECU sends a "A/C on" signal to the
module.
•
The automatic compressor-ECU detects how the
air conditioning is applying load to the engine,
and converts the information to a voltage signal
(High voltage= low load, Low voltage= high load).
This voltage signal is called "A/C switch 2 signal."
The PCM receives this A/C switch 2 signal from
the automatic compressor controller through
terminal 61, and determines the idle-up speed
according to the high or low air conditioning load.
AK000523
BL
UE-
WHITE
BL
UE-
WHITE
POWERTRAIN CONTROL
MODULE(PCM)
61
33
AUTOMATIC COMPRESSOR CONTROLLER
C-17
7 8
5
3 4
35
34
10 11 12
2122 23 24
13 14 15
25 26 27
16
28
17
18 19 20
29
30 31
32 33
36 37
38
9
1 2
6
C-40
(MU803781)
42 43
48 49 50 51 52 53 54 55 56 57
46
45
44
58 59
60 61 62 63
64 65 66
47
41
AK000280
CONNECTOR : C-40
PCM
AV
AK000566AB
CONNECTOR:C-17
MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-462
TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:)
•
Malfunction of the A/C control system.
•
Open or shorted circuit, or improper connector
contact.
•
PCM failed.
DIAGNOSIS
STEP 1. Check connector C-40 at PCM for damage.
Q: Is the connector in good condition?
YES : Go to Step 2.
NO : Repair or replace it. Refer to GROUP 00E, Harness
Connector Inspection(
). Then confirm that the
malfunction symptom is eliminated.
STEP 2. Check the output voltage at PCM harness side
connector C-40.
(1) Disconnect the connector C-40 and measure at the harness
side.
(2) Start the engine and run at idle.
(3) Turn the A/C switch "ON".
(4) Measure the voltage between terminal 61 and ground.
•
If atmospheric air temperature is 15
°
C (59
°
F) or less,
the voltage should be 1 volt or less.
•
If atmospheric air temperature is 18
°
C (65.4
°
F) or
more, the voltage should be battery positive voltage.
(5) Turn the A/C switch "OFF".
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES : Replace the PCM. Then confirm that the malfunction
symptom is eliminated.
NO : Refer to GROUP 55, Introduction To Heater, Air
Conditioning And Ventilation Diagnosis(
AKX01505
46 45 44
43 42
41
47
48
49
50
51
52
53
54
55
56
57
66 65 64
63 62 61 60
59
58
C-40 HARNESS
SIDE CONNECTOR
AE
MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-463
INSPECTION PROCEDURE 28: Fans (radlator fan, A/C condenser fan) are inoperative
AK000481
2 3
1
5
1
4
8
7
2
6
3
BLUE-ORANGE
BLUE-ORANGE
POWERTRAIN CONTROL
MODULE(PCM)
FAN CONTROLLER
5V
A-30
(MU802322)
C-04
MU801333
2
6
18
12
11
16
5 6
7 8
21
13
27
14
28
15
29
17
30
18
31
19
32
20
33
22
34
23
35
1
24
3
26
9
2
25
10
4
C-39
(MU803784)
AK000280
CONNECTOR : C-39
PCM
AW
ACX02501 AE
CONNECTOR : A-30
FAN
CONTROLLER
MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-464
CIRCUIT OPERATION
•
The PCM sends a duty signal to the fan controller
according to engine coolant temperature, vehicle
speed, and the condition of the A/C switch. (The
closer the average voltage at the terminal comes
to five volts, the higher the fan speed becomes).
TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:)
•
Malfunction of the fan motor relay.
•
Malfunction of the fan motor.
•
Malfunction of the fan controller.
•
Improper connector contact, open or short-
circuited harness wire.
•
PCM failed.
DIAGNOSIS
STEP 1. Check connector C-39 at PCM for damage.
Q: Is the connector in good condition?
YES : Go to Step 2.
NO : Repair or replace it. Refer to GROUP 00E, Harness
Connector Inspection(
). Then confirm that the
malfunction symptom is eliminated.
STEP 2. Check the output voltage at PCM harness side
connector C-39.
(1) Disconnect the connector C-39 and measure at the harness
side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 18 and ground.
•
Voltage should be between 4.8 and 5.2 volts. (Fan
rotates at high speed.)
(4) Connect a jumper cable between 18 and ground.
•
The fan should stop.
(5) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is the voltage and fan condition normal?
YES : Replace the PCM. Then confirm that the malfunction
symptom is eliminated.
NO : Go to Step 3.
AK000633 AE
CONNECTOR:C-04
AK000280
CONNECTOR : C-39
PCM
AW
AK000401
8 7
6 5
4 3
2
1
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
3534
33 32
30
29 28 27 26
25 24
C-39 HARNESS
SIDE CONNECTOR
AC
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