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OBD1 Honda ECU Pinout

1992-1995 Civic

1992-1995 Integra

1 3 5 7 9 11 13 15 17 19 21 23 25
2 4 6 / / 12 / 16 / 20 22 24 26
OBD1 ECU A (26 Pin) C404 Civic, C410 Integra
Pin Wire Color Terminal Name Description Test
1 BRN INJ1 Injector 1 Ignition On: 12V, Engine running: (-) Pulses
2 YEL INJ4 Injector 4 Ignition On: 12V, Engine running: (-) Pulses
3 RED INJ2 Injector 2 Ignition On: 12V, Engine running: (-) Pulses
4 ORN/WHT (Civic) to GRN/YEL VTS VTEC SOLENOID VALVE Low RPM: 0V, High RPM: 12V
5 LT BLU, BLU (Integra) INJ3 Injector 3 Ignition On: 12V, Engine running: (-) Pulses
6 ORN/BLK PO2SHTC Primary O2 Sensor Heater Control Ignition On: 12V, Operating Temperature: 0V
7 GRN/YEL (Civic), GRN/BLU (Integra) FLR Fuel Relay (Main Relay) 0V when activated, 12V resting
8 GRN/YEL (Civic), GRN/BLU (Integra) FLR Fuel Relay (Main Relay) Redundant
9 GRN/WHT to BLU/YEL (Civic), BLK/BLU (Integra) IACV Idle Air Control Valve Idle: 6 - 10V
11 ORN/BLU EGR Control Solenoid Drives EGR valve (VX) On: Duty controlled, Off: 0V
12 YEL/GRN (Civic) to GRN (Integra) FANC Radiator Fan Switch Fan Running: 0V
13 GRN/ORN MIL Malfunction Indicator Light On: 0V, Off: 12V
15 BLK/RED ACC A/C Compressor Clutch AC On: 0V, AC Off: 12V
16 WHT/YEL (Civic), WHT/GRN (Integra) ALTC Alternator Control 12 - 0V
17 PNK/BLU (GSR B18C1) IAB SOL Intake Air Bypass Below 5750RPM: 12V
19 WHT ICS Intake Control Solenoid (H22A)
20 RED to RED/BLK to RED PCS Purge Control Solenoid Coolant Temp > 154F: 12V when activated
21 RED/GRN (Civic) YEL/GRN (Integra) ICM Ignition Control Module Key (III): 12V, Engine running: pulses
22 RED/GRN (Civic only) ICM Ignition Control Module (redundant) Key (III): 12V, Engine running: pulses
23 BLK PG1 (Main Relay, VTP SW, G101) Power Ground 1 Less than 1V at all times
24 BLK PG2 (Main Relay, VTP SW, G101) Power Ground 2 Less than 1V at all times
25 YEL/BLK IGP2 Ignition Power Ground 2, Main Relay, Junction, INJ Key (II): 12V
26 BLK/RED (Civic), BRN/BLK (Integra) LG1 Logic Ground 1 Less than 1V at all times
1 / 5 7 9 11 13 15
2 / / 8 10 12 14 16
OBD1 ECU B (16 Pin) C405 Civic, C408 Integra
Pin Wire Color Terminal Name Description Test
1 YEL/BLK IGP1 Ignition Power 1, Main Relay, Junction, INJ Ignition On: 12V
2 BRN/BLK LG2 Logic Ground 2 Less than 1V at all times
5 BLU/RED AC Switch (ACS) Detects AC switch AC switch On: 0V, AC Switch Off: 12V
7 PNK/BLK CLSW Clutch Switch (VX)
8 BRN/RED (Civic), GRN (Integra) PSP SW Power Steering Pressure Switch When steering: 12V
9 BLU/WHT Starter Switch Signal (STS) Detects starting, Main Relay Engine cranking: 12V
10 YEL/BLU to YEL/WHT (Civic), ORN (Integra) VSS Vehicle Speed Sensor Ignition on, Front wheels rotating: 0 - 5V cycles
11 ORN CYP P Cylinder Position (Power) Engine running: Pulses
12 WHT CYP M Cylinder Position (Ground)
13 ORN/BLU TDC P Top Dead Center (Power) Engine running: Pulses
14 WHT/BLU TDC M Top Dead Center (Ground)
15 BLU/GRN CKP P Crank Position (Power) Engine running: Pulses
16 BLU/YEL CKP M Crank Position (Ground)
1 3 / 7 9 11 13 15 17 19 21
2 4 6 8 10 12 14 16 18 20 22
OBD1 ECU D (22 Pin) C405 Civic, C409 Integra
Pin Wire Color Terminal Name Description Test
1 WHT/BLU VBU Voltage Backup ECU Power source 12V
2 GRN/WHT BKSW Brake Switch signal Brake pressed: 12V
3 RED/BLU KS Knock Sensor (GSR, Type R) Knock present: pulses
3 BLU/YEL to WHT (Civic VX) LAF LABEL 5-wire O2 Sensor (VX) O2 Unplugged, jumpered to D22: .3 - 4.9V
4 BRN (Civic), BRN/WHT (Integra) Service Check Signal (SCS) Enables Diagnostic mode Jumpered: 0V, Not jumpered: 5V or Battery voltage
6 ORN/BLU (Civic) to BLU/BLK VTP SW (USDM) VTEC Pressure Switch VTEC ON: 12V
7 LT BLU DLC Data Link Connector
8 WHT/BLU (Civic VX) LAF VS+ 5-wire O2 Sensor (VX) Jumpered to D22: > .5V
9 PNK to BLU (Civic), WHT/RED (Integra) ALT F Alternator FR Signal Engine running: voltage dependent on electrical load
10 GRN/RED ELD Electric Load Detector Parking Lights On, Idle: 2.5 - 3.5V, Headlights On: 1.5 - 2.5V
11 LT GRN to RED/BLU (Civic), RED/BLK (Integra) TPS Throttle Position Sensor Fully Open: 4.8V, Closed: .5V
12 WHT/BLK EGRL (VX) Exhaust Gas Recirculation Valve Position Idle: 1.2V
13 RED/WHT ECT Engine Coolant Temp .1 - 4.8V
14 WHT (Civic), WHT/RED (Integra) PHO2S Primary Heated O2 Sensor Signal Full throttle, Operating temperature > .6V, Decel > .4V
14 ORN/BLU (Civic VX) LAF IP+ 5-wire O2 (VX)
15 RED/YEL IAT Intake Air Temperature .1 - 4.8V
16 BLU/GRN to ORN (Civic VX) LAF IP-, VS- 5-wire O2 (VX) Jumpered TO D22: > .5V
17 WHT (Civic) or WHT/YEL (Integra) MAP Manifold Absolute Pressure Ignition on: 3V, Idle: ~1V
18 PNK/GRN to LT BLU SIL Upshift Light (CX, VX)
19 YEL/GRN (Civic) or YEL/WHT to YEL/RED (Integra) VCC1 Sensor Voltage 1 (MAP) Ignition on: 5V
20 YEL/WHT (Civic), YEL/BLU (Integra) VCC2 Sensor Voltage 2 (TPS) Ignition on: 5V
21 GRN/BLU (Civic) to GRN/WHT (Integra) SG1 Sensor Ground 1 Less than 1V at all times
22 GRN/WHT (Civic), GRN/BLU (Integra) SG2 Sensor Ground 2 Less than 1V at all times

O2 Sensors

Civic VX "Wideband" LAF Sensor C111 "5 Wire O2" or "7 Wire O2" engine wire harness side
WHT to BLU/YEL LABEL
D3
 GRN/WHT SG2
D22
 BLK PG1
A23
 YEL/BLK to ORN/BLK HTCNTL
A6
ORN to BLU/GRN IP-,/VS-
D16
 ORN/BLU IP+
D14
 WHT/BLU VS+
D8
Heated O2 Sensor
WHT
D3
 GRN/WHT
D22
ORN
D16
 ORN/BLU
D14

MAP Sensor and TPS

1 2 3
MAP Sensor
Pin Wire Color Terminal Name Description
1 WHT MAP Signal D17
2 GRN/WHT or GRN/BLU (D15B7) SG1 Sensor Ground D21
3 YEL/RED or YEL/GRN (D15B7) VCC1 Sensor Voltage D19
1 2 3
TPS
Pin Wire Color Terminal Name Description
1 YEL/WHT VCC2 Sensor Voltage D20
2 RED/BLU TPS Signal D11
3 GRN/WHT SG2 Sensor Ground D22

Distributor

1 2 3 4
/ 6 7 8
Distributor C107 Civic, C110 Integra
Pin Wire Color Terminal Name Description
1 YEL/GRN ICM A21
2 BLU/GRN CKP P B15
3 ORN/BLU TDC P B13
4 ORN CYL P B11
6 BLU/YEL CKP M B16
7 WHT/BLU TDC M B14
8 WHT CYP M B12

Main Relay

1 2 3
4 5 6 7
Main Relay
Pin Wire Color Terminal Name Description
1 GRN/YEL FLR1, FLR2 A7, A8
2 BLU/WHT STS Under dash Fuse 18, B9
3 BLK PG1, PG2 A23, A24, G101
4 YEL/GRN FUEL PUMP
5 BLK/YEL IG1 Under dash Fuse 12
6 YEL/BLK IGP1, IGP2 A25, B1, INJ, O2
7 YEL/WHT Constant 12V Under hood ECU Fuse 31

Strut Tower Plugs

1 2 3
4 5 6 7
8 9 10 11
12 13 14
Driver-side round plug C304 / C126 Civic, C305 / C127 Integra
Pin Wire Color Terminal Name Description
1 BLK/YEL Alternator From Alt to Dash Fuse
2 WHT/BLU Battery Warning Light Gauge Cluster to Alternator
3 RED to RED/BLK to RED PCS A20
3 PNK/BLU IAB Solenoid A17 B18C1
4 GRN/WHT to BLU/YEL, BLK/BLU (Integra) IACV A9
5 BLK/YEL IG1 (Key) Alternator Dash Fuse 24 to VSS, Main Relay, ELD
6 YEL/BLU to YEL/WHT, ORN (Integra) VSS B10
7 BLU (Integra) Tachometer Engine Speed ICM to Gauge Cluster
8 YEL/RED Oil Warning Light Gauge Cluster to Oil Pressure Sw
9 YEL/GRN, GRN (Integra) FANC A12, Radiator Fan Switch
10 BLK PG2 A23, A24 to G101, VTP SW
11 YEL/GRN to GRN Coolant Temp Sending Unit Gauge Cluster
12 YEL, YEL/BLK (Integra) IGP1 and 2 (AUTO) B1 to INJ
13 GRN/BLK LCB (AUTO) A18
14 YEL/BLK, YEL (Integra) LCA (AUTO) A19
1 2 3
4 5 6 7
8 9 10
Passenger-side (10 Pin) round plug C222 / C102
Pin Wire Color Terminal Name Description
1 BRN/BLK LG 1 or 2 A26 or B2 Thermostat Housing
2 WHT/RED PHO2S D14
3 BRN/BLK LG 1 or 2 A26 or B2 Thermostat Housing
4 ORN CYP P B11
5 WHT CYP M B12
6 ORN/BLU TDC P B13
7 WHT/BLU TDC M B14
8 BLU/GRN CKP P B15
9 BLU/YEL CKP M B16
10 RED/BLU KS Knock Sensor D3
1 2
3 4
Passenger-side C221 / C101
Pin Wire Color Terminal Name Description
1 RED INJ2 A3
2 BRN INJ1 A1
3 YEL INJ4 A2
4 BLU INJ3 A5
1 2 3
4 5 6 7
8 9 10 11
12 13 14
Passenger-side (14 Pin) round plug C223 / C103
Pin Wire Color Terminal Name Description
1 WHT/GRN ALT C A16
2 ORN/BLK PO2SHTC A6
3 GRN/YEL VTS A4 VTEC Solenoid
4 GRN/WHT SG1 - MAP D21
5 WHT/YEL MAP D17
6 YEL/WHT / YEL/RED VCC1 to MAP D19
7 BLU/BLK VT PSW D6 VTEC Pressure Switch
8 RED/BLK TPS D11
9 GRN/BLU - GRN/BLK SG2 to PHO2S D22
10 YEL/BLU VCC2 to TPS D20
11 YEL/GRN ICM A21
12 RED/YEL IAT D15
13 RED/WHT ECT D13
14 WHT/RED ALT F D9