DI–18

DIAGNOSTICS – ENGINE
DI0II–03

TERMINALS OF ECM
1. STANDARD VALUE OF ECM TERMINALS

Connectors of the ECM are water–proof and are the bolt
type. For water–proof type connectors, in order to mea-
sure the voltage of ECM terminals and the resistance of
connected parts, connect the inspection check harness
between the ECM and vehicle wire harness, then perform
the inspection.
FI6898

The inspection method of inserting a tester probe from the
other side of connector noticeably reduces the water–
proof ability.
Disconnect the connector by fully loosening the bolt.

2. PREPARATION
(a) Turn the ignition switch to LOCK position.
(b) Turn up the passenger side floor mat.
(c) Remove the ECM protector.
(d) Disconnect the connectors from the ECM.
After completely loosening the bolt, the 2 parts of connec-
tor can be separated.
ECM
P10493

NOTICE:
Check Harness A
Do not pully the wire harness when disconnecting the
ECM connector.

When disconnecting the connector, the ECM’s back-
up power source is cut off, so the DTCs, etc. recorded
in the ECM memory are canceled.

Never insert a tester probe or male terminal used for
inspection purposes into the female terminal of the
FI6451 vehicle wire harness. Otherwise, the female terminal
may be widened, which can result in faulty connec-
tion.

1996 LEXUS GS300 (RM453U)

 DI–19
DIAGNOSTICS – ENGINE

Before Connection After Connection (e) Connect the Check Harness A between ECM and con-
Female nector of vehicle wire harness.
Bolt Connector
Collar SST 09990–01000
Stopper HINT:
Nut The arrangement of the DLC1 terminals are the same as those
of the ECM (See page DI–18).
(f) Disconnect the Check Harness A.
Male (g) Reconnect the connectors to the ECM.
Connector FI6522 (1) Match the male connector correctly with female
connector, then press them together.
(2) Tighten the bolt.
Make sure the connector is completely connected,
by tightening the bolt until there is a clearance of
less than 1 mm (0.04 in.) between bottom of the
male connector and end of the female connector.

(h) Install the ECM protector and floor mat.

Less Than 1 mm (0.04 in.)

FI6523

1996 LEXUS GS300 (RM453U)

DI–20
DIAGNOSTICS – ENGINE

ECM Terminals
B (E8) A (E7)

20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 10 9 8 7 6 5 4 3 2 1
40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11
60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 30 29 28 27 26 25 24 23 22 21
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 40 39 38 37 36 35 34 33 32 31

FI6460

Symbols (Terminals No.) Wiring Color Condition STD Voltage (V)

BATT (A33) – E1 (B69) W–L – BR Always 9 – 14
IGSW (A1) – E1 (B69) B–O – BR
IG switch
it h ON 9 – 14
+B (A31) – E1 (B69) B–R – BR
VC (B41) – E2 (B65) L–R – BR IG switch ON 4.5 – 5.5
IG switch ON and apply vacuum to the throttle opener
–0.1 – 3.0
Main throttle valve fully closed
IDL1 (B64) – E2 (B65) P L – BR
P–L
IG switch ON
9 – 14
Main throttle valve fully opened
IG switch ON
–0.1 – 3.0
Sub throttle valve fully closed
IDL2 (B63) – E2 (B65) BR – BR
IG switch ON
9 – 14
Sub throttle valve fully opened
IG switch ON
0.3 – 0.8
VTA1 (B43) – E2 (B65) B R – BR
B–R Main or sub throttle valve fully closed
VTA2 (B42) – E2 (B65) B–W – BR IG switch ON
3.2 – 4.9
Main or sub throttle valve fully opened

VG (B66) – EVG (B28) L–R – Y–G Idling, P or N position, A/C switch OFF 0.7 – 1.7
Idling,
THA (B45) – E2 (B65) L–W – BR 0.5 – 3.4
Intake air temperature 0°C (32°F) to 80°C (176°F)
Idling,
THW (B44) – E2 (B65) P – BR 0.2 – 1.0
Engine coolant temperature 60°C (140°F) to 120°C (248°F)

THG (B46) – E2 (B65) L–B – BR Idling after warming up 1.0 – 4.0

STA (B77) – E1 (B69) B–W – BR Cranking 6.0 or more

#10 (B20) – E01 (B80) R–L – W–B

IG switch ON 9 – 14
#20 (B19) – E01 (B80) Y – W–B
#30 (B18) – E01 (B80) G – W–B
W B
#40 (B17) – E01 (B80) W – W–B Pulse generation
#50 (B16) – E01 (B80) R – W–B Idling
(See page DI–58)
#60 (B15) – E01 (B80) B–R – W–B
Pulse generation
IGT (B57) – E1 (B69) G–W – BR Idling
(See page DI–106)
IG switch ON 4.5 – 5.0
IGF (B58) – E1 (B69) G–Y – BR Pulse generation
Idling
(See page DI–106)
G1 (B26) – G– (B7) R–G Pulse generation
Idling
G2 (B25) – G– (B7) W–G (See page DI–68)
NE (B27) – G– (B7) B–G Pulse generation
Idli
Idling
NE2 (B4) – NE2– (B5) B–W (See page DI–68)

1996 LEXUS GS300 (RM453U)

 DI–21
DIAGNOSTICS – ENGINE

Symbols (Terminals No.) Wiring Color Condition STD Voltage (V)

M–REL (A24) – E1 (B69) B–L – BR IG switch ON 9 – 14
IG switch ON Below 0.5
FPC (A22) – E1 (B69) G–R – BR Pulse generation
Idling
(0 and 4.0 – 5.5)
DI (A21) – E1 (B69) LG–R – BR Idling 7.0 or more
ACIS (B39) – E01 (B80) R–B – W–B IG switch ON 9 – 14
PRG (B74) – E01 (B80) P–L – W–B IG switch ON 9 – 14
Idling Below 2.0
EGR (B75) – E01 (B80) R W – W–B
R–W W B
Engine speed at 3,500 rpm 9 – 14
ISC1 (B35) – E01 (B80) R–Y – W–B
ISC2 (B34) – E01 (B80) Y–R – W–B Pulse generation
Idling, When A/C switch ON or OFF
ISC3 (B33) – E01 (B80) Y–G – W–B (See page DI–94)
ISC4 (B32) – E01 (B80) Y–B – W–B
OX1 (B48) – E1 (B69) B – BR
Maintain engine speed at 2,500 rpm for 2 min. after Pulse generation
OX2 (B47) – E1 (B69) W – BR
warming up (See page DI–47)
OXL2 (A30) – E1 (B69) B – BR

HT1 (B71) – E01 (B80) R – W–B Idling after warning up Below 3.0
HT2 (B72) – E01 (B80) L–Y
L Y – W–B
W B
HTL2 (A36) – E01 (B80) Y–G – W–B IG switch ON 9 – 14

KNK1 (B50) – E1 (B69) R – BR Pulse generation

Idling
KNK2 (B49) – E1 (B69) GR – BR (See page DI–65)
IG switch ON
9 – 14
Other shift position in ”P” or ”N” position
NSW (B76) – E1 (B69) B – BR
IG switch ON
–0.1 – 3.0
Shift position in ”P” or ”N” position

IG switch ON Pulse generation

SP1 (A2) – E1 (B69) V–W – BR
Rotate driving wheel slowly (See page DI–92)

TE1 (A20) – E1 (B69) L–R – BR IG switch ON 9 – 14

Idling 9 – 14
W (A6) – E01 (B80) B Y – W–B
B–Y W B
IG switch ON –0.1 – 3.0
OD1 (A12) – E1 (B69) V – BR IG switch ON 9 – 14
A/C switch ON (At idling) 7.5 – 14
AC1 (A34) – E1 (B69) B W – BR
B–W
A/C switch OFF –0.1 – 1.5
IG switch ON
7.5 – 14
Brake pedal depressed
STP (A4) – E1 (B69) G W – BR
G–W
IG switch ON
Below 1.5
Brake pedal released
A/C switch ON (At idling) –0.1 – 3.0
ACMG (A23) – E1 (B69) W – BR
A/C switch OFF 9 – 14
TR (A13) – E1 (B69) P – BR IG switch ON 9 – 14
IG switch ON
0.3 – 0.8
VTO1 (A40) – E2 (B65) P L – BR
P–L Main or sub throttle valve fully closed
VTO2 (A39) – E2 (B65) Y–R – BR IG switch ON
3.2 – 4.9
Main or sub throttle valve fully opened

NEO (A38) – E1 (B69) BR–W – BR IG switch ON 4.5 – 5.5

IG switch ON 9 – 14
FPU (B73) – E01 (B80) L–W
W–B
B
Restarting at high engine coolant temperature Below 2.0

1996 LEXUS GS300 (RM453U)

DI–22
DIAGNOSTICS – ENGINE

Defogger switch and taillight switch ON 7.5 – 14

ELS1 (A15) – E1 (B69) LG B – BR
LG–B
Defogger switch and taillight switch OFF –0.1 – 1.5
SDL (A8) – E1 (B69) W – BR During transmission Pulse generation

1996 LEXUS GS300 (RM453U)