MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-602
INSPECTION PROCEDURE 27: Incorrect Idle Speed When the A/C is Operating (A/C Switch 2 Signal)
.
CIRCUIT OPERATION
•
The ECM <M/T> or PCM <A/T> 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 ECM <M/T> or PCM <A/T> receives
this A/C switch 2 signal from the automatic com-
pressor controller through terminal 65 <M/T> or
terminal 61 <A/T>, and determines the idle-up
speed according to the high or low air condition-
ing load.
AK000714
BL
UE-
WHITE
BL
UE-
WHITE
ENGINE CONTROL
MODULE (ECM) <M/T>
OR
POWERTRAIN CONTROL
MODULE (PCM) <A/T>
65 <M/T>
61 <A/T>
33
AUTOMATIC COMPRESSOR CONTROLLER
C-28
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
65
43
50
42
49
41
48
60 61
64
46 47
58 59
67 68
45
56
66
52
51
44
53
62
54
63
57
55
C-58 <M/T>
(MU803782)
C-55 <A/T>
(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
A/C Switch 2 Signal
AK000225
CONNECTOR : C-58<M/T>, C-55<A/T>
C-55
C-58
PCM<A/T>
ECM<M/T>
AI
AK000733AC
CONNECTOR:C-28
