Jul 11 2008
OBD1 Honda/Acura ECU Pinouts
KOEO = Key on; Engine OFF
KOER = Key on; Engine Running
|
Pin
|
Function
|
Color
|
Voltage
|
|
A1
|
INJ1
|
Brown
|
Battery Voltage with KOEO
|
|
A2
|
INJ4
|
Yellow
|
Battery Voltage with KOEO
|
|
A3
|
INJ2
|
Red
|
Battery Voltage with KOEO
|
|
A4
|
VTS - VTEC Solenoid
|
Green/Yellow
|
N/A
|
|
A5
|
INJ3
|
Blue
|
Battery Voltage with KOEO
|
|
A6
|
PO2SHTC - O2 Sensor Heating Element
|
Orange/White
|
Battery Voltage with KOEO
|
|
A7
|
FLR1- Fuel Pump
|
Green/Black
|
Battery Voltage with KOEO
|
|
A8
|
Empty
|
-
|
-
|
|
A9
|
IACV
|
Black/Blue
|
10V KOEO with warm engine
|
|
A10
|
Empty
|
-
|
-
|
|
A11
|
EGR
|
Red
|
N/A
|
|
A12
|
FANC - Engine Coolant Temp. Switch
|
Blue/Red
|
N/A
|
|
A13
|
CEL
|
Blue/White
|
N/A
|
|
A14
|
Empty
|
-
|
-
|
|
A15
|
ACC - A/C Clutch
|
Red/Blue
|
N/A
|
|
A16
|
ALT C - Alternator
|
White/Green
|
N/A
|
|
A17
|
IAB - IAB Solenoid
|
Pink
|
N/A
|
|
A18
|
Auto Lock Up Solenoid
|
Orange/Red
|
N/A
|
|
A19
|
Intake Control Solenoid
|
White
|
Battery Voltage with KOEO
|
|
A20
|
PCS EVAP Purge Control Solenoid
|
Red/Green
|
N/A
|
|
A21
|
ICM - Ignition Control Module
|
Yellow/Green
|
10V KOEO
|
|
A22
|
Ignitor “
|
“
|
“
|
|
A23
|
PG1 - Ground
|
Black
|
< 1V
|
|
A24
|
PG2 - Ground
|
“
|
“
|
|
A25
|
IGP2 - Battery Positive to Main Relay
|
Yellow/Black
|
Battery Voltage with KOEO
|
|
A26
|
LG1 - Ground
|
Black/Red
|
<1V
|
|
B1
|
IGP2 - To A25
|
Yellow/Black
|
Battery Voltage with KOEO
|
|
B2
|
LG2 - Ground/Shields for CYP/TDC
|
Brown/Black
|
<1V
|
|
B3
|
Upshift/Downshift
|
Orange
|
N/A
|
|
B4
|
“
|
Pink
|
N/A
|
|
B5
|
ACS - A/C Switch
|
Blue/Black
|
5V = KOEO/A/C Off; <1V KOER/A/C On
|
|
B6
|
Empty
|
-
|
-
|
|
B7
|
Park/Neutral Switch
|
Light Green
|
<1V KOEO; 5V KOER
|
|
B8
|
PSPSW - Power Steering Pressure Switch
|
Red/Green
|
0V KOEO; Battery Voltage KOER while turning
|
|
B9
|
Starter Signal
|
Blue/Red
|
Battery Voltage when in Start Position
|
|
B10
|
VSS - Vehicle Speed Sensor
|
Orange
|
Pulses 0-12V while spinning front-left wheel
|
|
B11
|
CYP P
|
Orange
|
CYP Sensor Input
|
|
B12
|
CYP M
|
White
|
CYP Sensor Signal
|
|
B13
|
TDC P
|
Orange/Blue
|
TDC Sensor Input
|
|
B14
|
TDC M
|
White/Green
|
TDC Sensor Signal
|
|
B15
|
CKP P
|
Blue/Green
|
CKP Sensor Input
|
|
B16
|
CKP M
|
Blue/Yellow
|
CKP Sensor Signal
|
|
D1
|
VBU - Back Up Power
|
White/Yellow
|
Battery Voltage at All Times
|
|
D2
|
BKSW - Brake Switch
|
Green/White
|
Battery Voltage at All Times
|
|
D3
|
KS - Knock Sensor
|
Red/Blue
|
N/A
|
|
D4
|
SCS - Service Check Connector
|
Brown/White
|
Manual 5V; Auto 11V
|
|
D5
|
Empty
|
-
|
-
|
|
D6
|
VTM - VTEC Pressure Switch
|
Light Blue
|
N/A
|
|
D7
|
TXD/RXD - Data Link Connector
|
Light Green/Red
|
N/A
|
|
D8
|
Empty
|
-
|
-
|
|
D9
|
ALT F - Alternator
|
White/Red
|
4.5V KOEO; Decreases Under Electrical Load
|
|
D10
|
ELD - Electrical Load Detector
|
Green/Black
|
N/A
|
|
D11
|
TPS
|
Red/Black
|
0.5V Closed; 4.5V Wide Open
|
|
D12
|
EGR Valve Lift Sensor
|
White/Black
|
1.2V KOEO
|
|
D13
|
ECT - ECT Sensor Input
|
Yellow/Blue
|
5V KOEO
|
|
D14
|
PHO2S - O2 Sensor Heater
|
White
|
0.4-0.5V Cold; 0.1V Warm
|
|
D15
|
IAT
|
Red/Yellow
|
0.05-4.5V Depending on Temperature
|
|
D16
|
VREF
|
-
|
-
|
|
D17
|
MAP
|
White/Blue
|
3V KOEO
|
|
D18
|
Transmission Control Module (Auto)
|
Light Green/Black
|
N/A
|
|
D19
|
Reference Voltage
|
Red/White
|
5V KOEO
|
|
D20
|
Reference Voltage
|
Yellow/White
|
5V KOEO
|
|
D21
|
Sensor Ground
|
Blue/White
|
<1V
|
|
D22
|
Sensor Ground
|
Green/White
|
<1V
|
