LEXUS SC400 1991 Service Repair Manual

STANDARD VALUE OF ECU TERMINAL
 

Terminals
 

Symbols
 

Wiring
Color 

Condition
 

Standard
Value
 

T9±1 

Si 

B 


Tilt & telescopic ECU & power seat ECU
communication 

0 V
e12 V
 T9±2 e DSW e R±Be Driver's door open Below 1 V
 
T9 2 e
Body Ground 
DSW e
Body Ground 
RBe
Body GroundDriver's door closed1014 V
 T9±3 eT9±8 M1 eECU±E Pe BR±B Driving position memory & return switch ON Below 1 V
 T9±3eT9±8 M1eECU±E PeBR±B Driving position memory & return switch OFF 10
~ 14 V
 T9±4
eT9±5 ASW eE1 V±W eBR Unlock warning switch ON, auto switch ON 10 ~ 14 V
 T9±4eT9±5 ASWeE1 V±WeBR Unlock warning switch ON, auto switch OFF Below 1 V
 T9±5 E1 BR Always Below 1 V
 

T9±6
eT9±5
 

Te S
eE1
 

Y±R
eBR
 


Unlock warning switch ON, telescopic fully
forward 

Below 2 V
 
T9±6eT9±5
 
TeSeE1
 
Y±ReBR
 Unlock warning switch ON, telescopic fully
backward 4±6 V
 
T9±7
eT9±5
 
TiS eE1
 
P±L eBR
 Unlock warning switch ON, tilt fully raised Below 2 V T9±7eT9±5 TiSeE1 P±LeBR Unlock warning switch ON, tilt fully lowered 4±6 V T9±8 ECU±E BR±B Always Below 1 V 

T9±9
 

So
 

W
 

Tilt & telescopic ECU & power seat ECU
communication 

0 V
e12 V
 T9±10 e UWSW e Ye Ignition key inserted in the key cylinder Below 1 V
 T9 10 e
Body Ground UWSW e
Body Ground Ye
Body Ground Ignition key pulled out from the key cylinder 10
~ 14 V
 
T9±11 eT9±8
 
MRY eECU±E
 
R±Y eBR±B
 Auto set switch ON Below 1 V
 T9±11eT9±8 MRYeECU±E R±YeBR±B Auto set switch OFF 10 ~ 14 V
 
T9±12 eT9±8
 
M2 eECU±E
 
P±B eBR±B
 Driving position memory & return switch ON Below 1 V
 T9±12eT9±8 M2eECU±E P±BeBR±B Driving position memory & return switch OFF 10 ~ 14 V
 


 


 


 


Unlock warning switch ON
Telescopic extend by manual switch 

2.6 V
 


 


 


 


Unlock warning switch ON
Tilt up by manual switch 

3.5 V
 T9±16
eT9±17 MSW eVC V±Y eR±W Unlock warning switch ON
Telescopic contracted by manual switch 4.2 V
 


 


 


 

Unlock warning switch ON
Tilt down by manual switch 

4.6 V
 


 


 


 


Unlock warning switch ON, manual switch
OFF 

4±6 V
±
STEERING STEERING COLUMNSR±49
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STANDARD VALUE OF ECU TERMINAL
 

Terminals
 

Symbols
 


Wiring
Color 

Condition
 


Standard
Value
 T9±17 eT9±5 Vc eE1 R±W eBR Unlock warning switch ON 4±6 V
 T9±17eT9±5 VceE1 R±WeBR Unlock warning switch OFF Below 1 V
 T9±18 ECU±B R Always 10 ~ 14 V
 T10±1 e IGe B±R e Ignition switch ON 10 ~ 14 V
 
T10 1 e
Body Ground 
IGe
Body Ground 
BR e
Body Ground Ignition switch OFF Below 1 V
 

T10±2
e
Body Ground
 

Te M+e
Body Ground
 

L±B
e
Body Ground
 


Unlock warning switch ON, telescopic
forward 

10 ~ 14 V
 Body Ground Body Ground Body Ground Except above mention Below 1 V
 T10±3
e TiM±e R±Le Unlock warning switch ON, tilt down 10 ~ 14 V
 
T10 3 e
Body Ground 
TiMe
Body Ground 
RLe
Body Ground Except above mention Below 1 V
 T10±4 +B L±W Always 10 ~ 14 V
 T10±6 e Pe GR e Ignition switch ON, shift lever ªPº position 10 ~ 14 V
 
T10 6 e
Body Ground 
Pe
Body Ground 
GR e
Body Ground Ignition switch ON, except above mention Below 1 V
 T10±6 e Pe GR e Ignition switch ON, PKB lever pulled Below 1 V
 
T10 6 e
Body Ground 
Pe
Body Ground 
GR e
Body Ground Ignition switch ON, PKB lever released 10 ~ 14 V
 T10±7 GND W±B Always Below 1 V
 T10±10 e TiM+e R±Be Unlock warning switch ON, tilt up 10 ~ 14 V
 
T10 10 e
Body Ground 
TiMe
Body Ground 
RBe
Body Ground Except above mention Below 1 V
 T10±11 e
Body Ground
 Te M±e
Body Ground
 L±Ye
Body Ground
 Unlock warning switch ON, telescopic
backward 10 ~ 14 V
 Body Ground Body Ground Body Ground Except above mention Below 1 V
TILT & TELESCOPIC ECU
SR±50±
STEERING STEERING COLUMN
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±MEMO±
±
STEERING STEERING COLUMNSR±51
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MATRIX CHART OF PROBLEM SYMPTOMS
Perform troubleshooting of the circuits for the applicable problem symptom in t\
he order given in the chart
below. Proceed to the page number given for each circuit.
SR±62SR±66 SR±70
SR±72
SR±74
SR±52±
STEERING STEERING COLUMN
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HINT

If the instruction ªProceed to next circuit inspection shown on matrix chartº is given in the flo\
w chart
for each circuit, proceed to the circuit with the next highest number in th\
e table to continue the check.

If the trouble still reappears even through there are no abnormalities i\
n any of the other circuits, then
check and replace the Tilt & Telescopic ECU as the last step.
SR±76
SR±76
SR±80 SR±84
SR±88 SR±90
SR±92
SR±94
SR±96
SR±98
SR±100
IN±38
±
STEERING STEERING COLUMNSR±53
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LOCATION OF CONNECTORS
LOCATION OF CONNECTORS IN ENGINE COMPARTMENT
SC400
SR±54±
STEERING STEERING COLUMN
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±
STEERING STEERING COLUMNSR±55
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LOCATION OF CONNECTORS IN BODY
SR±56±
STEERING STEERING COLUMN
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±
STEERING STEERING COLUMNSR±57
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LOCATION OF CONNECTORS IN INSTRUMENT PANEL
SR±58±
STEERING STEERING COLUMN
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