GARAGE REFERENCE // PRINTABLE
P08 ECU Pinout Card.
The full OBD-1 chart — every pin on all three ECU plugs with wire colors and the reading you should see, plus the shock-tower round plugs that carry those wires through the firewall. Click around the explorer, then print the card for the toolbox lid.
Plug explorer — click any pin
ECU connectors + shock-tower plugs · terminal view, harness side · the “show me” link drops you to the chart
C103 / C223 · passenger shock tower · 14-pin
3
VTS VTEC solenoid
Passenger round plug · pin 3
GRN/YEL
A4
Pin it to the wall — the tower plugs as holographic posters, full color
P08 ECU Pinout — JDM D15B SOHC VTEC (OBD-1)
37820-P08-000 · full chart + shock-tower plugs · d15b-detail-hub
Connector A — 26-pin
Injectors · VTEC · power
| Pin | Signal | Wire | What it does | Expect | Plug |
|---|---|---|---|---|---|
| A1 | INJ1 | BRN | Injector 1 | Key on: 12V · running: ground pulses | |
| A2 | INJ4 | YEL | Injector 4 | Key on: 12V · running: ground pulses | |
| A3 | INJ2 | RED | Injector 2 | Key on: 12V · running: ground pulses | |
| A4 | VTS | ORN/WHT | VTEC solenoid valve | Low rpm: 0V · VTEC engaged: 12V | |
| A5 | INJ3 | LT BLU | Injector 3 | Key on: 12V · running: ground pulses | |
| A6 | PO2SHTC | ORN/BLK | O2 heater control | At operating temp: 0V | |
| A7 | FLR | GRN/YEL | Fuel-injection main relay | 0V when activated · 12V resting | |
| A8 | FLR | GRN/YEL | Main relay (redundant) | 0V when activated · 12V resting | |
| A9 | IACV | GRN/WHT | Idle air control valve | Idle: 6–10V | |
| A11not on P08 | EGR | ORN/BLU | EGR control solenoid (VX only) | Duty-controlled when on | |
| A12 | FANC | YEL/GRN | Radiator fan switch | Fan running: 0V | |
| A13 | MIL | GRN/ORN | Check-engine light driver | Light on: 0V · off: 12V | |
| A15 | ACC | BLK/RED | A/C compressor clutch | A/C on: 0V · off: 12V | |
| A16 | ALTC | WHT/YEL | Alternator control | 12V → 0V | |
| A17not on P08 | IAB SOL | PNK/BLU | Intake air bypass (GSR B18C1) | Below 5750 rpm: 12V | |
| A19not on P08 | ICS | WHT | Intake control solenoid (H22A) | Coolant > 154°F: 12V when active | |
| A20 | PCS | RED | Purge control solenoid | Duty-controlled when on | |
| A21 | ICM | RED/GRN | Ignition control module | Start (III): 12V · running: pulses | |
| A22 | ICM | RED/GRN | Ignition control (redundant) | Start (III): 12V · running: pulses | |
| A23 | PG1 | BLK | Power ground 1 (to G101) | < 1V at all times | |
| A24 | PG2 | BLK | Power ground 2 (to G101) | < 1V at all times | |
| A25 | IGP2 | YEL/BLK | ECU power from main relay | Key on (II): 12V | |
| A26 | LG1 | BLK/RED | Logic ground 1 | < 1V at all times |
Connector B — 16-pin
Distributor position sensors · VSS
| Pin | Signal | Wire | What it does | Expect | Plug |
|---|---|---|---|---|---|
| B1 | IGP1 | YEL/BLK | ECU power from main relay | Key on: 12V | |
| B2 | LG2 | BRN/BLK | Logic ground 2 | < 1V at all times | |
| B5 | ACS | BLU/RED | A/C switch input | A/C on: 0V · off: 12V | |
| B7not on P08 | CLSW | PNK/BLK | Clutch switch (VX only) | — | |
| B8 | PSP SW | BRN/RED | Power-steering pressure switch | Steering loaded: 12V | |
| B9 | STS | BLU/WHT | Starter switch signal | Cranking: 12V | |
| B10 | VSS | YEL/BLU | Vehicle speed sensor | Wheels turning: 0–5V cycles | |
| B11 | CYP P | ORN | Cylinder position sensor (power) | Running: pulses | |
| B12 | CYP M | WHT | Cylinder position sensor (ground) | — | |
| B13 | TDC P | ORN/BLU | TDC sensor (power) | Running: pulses | |
| B14 | TDC M | WHT/BLU | TDC sensor (ground) | — | |
| B15 | CKP P | BLU/GRN | Crank position sensor (power) | Running: pulses | |
| B16 | CKP M | BLU/YEL | Crank position sensor (ground) | — |
Connector D — 22-pin
Analog sensor inputs
| Pin | Signal | Wire | What it does | Expect | Plug |
|---|---|---|---|---|---|
| D1 | VBU | WHT/BLU | ECU backup power (constant) | 12V at all times | |
| D2 | BKSW | GRN/WHT | Brake switch input | Brake pressed: 12V | |
| D3not on P08 | KS | RED/BLU | Knock sensor (GSR / Type R) | Knock: pulses | |
| D4 | SCS | BRN | Service check signal — jumper to read codes | Jumpered: 0V · open: 5V | |
| D6 | VTP SW | ORN/BLU | VTEC oil-pressure switch | VTEC on: 12V | |
| D7 | DLC | LT BLU | Data link connector | — | |
| D8not on P08 | LAF VS+ | WHT/BLU | 5-wire O2 sensor (VX only) | Jumpered to D22: > 0.5V | |
| D9 | ALT F | PNK | Alternator FR signal | Running: varies with load | |
| D10 | ELD | GRN/RED | Electrical load detector | Park lights idle: 2.5–3.5V · headlights: 1.5–2.5V | |
| D11 | TPS | LT GRN | Throttle position sensor | Closed: 0.5V · wide open: 4.8V | |
| D12not on P08 | EGRL | WHT/BLK | EGR valve lift sensor (VX only) | Idle: 1.2V | |
| D13 | ECT | RED/WHT | Engine coolant temperature | 0.1–4.8V by temp | |
| D14 | PHO2S | WHT | Primary O2 sensor signal | Full throttle warm: > 0.6V · decel: < 0.4V | |
| D15 | IAT | RED/YEL | Intake air temperature | 0.1–4.8V by temp | |
| D16not on P08 | LAF IP−/VS− | BLU/GRN | 5-wire O2 return (VX only) | Jumpered to D22: > 0.5V | |
| D17 | MAP | WHT | Manifold absolute pressure | Key on: ~3V · idle: ~1V | |
| D18not on P08 | SIL | PNK/GRN | Upshift light (CX/VX) | — | |
| D19 | VCC1 | YEL/GRN | Sensor 5V supply (MAP) | Key on: 5V | |
| D20 | VCC2 | YEL/WHT | Sensor 5V supply (TPS) | Key on: 5V | |
| D21 | SG1 | GRN/BLU | Sensor ground 1 | < 1V at all times | |
| D22 | SG2 | GRN/WHT | Sensor ground 2 | < 1V at all times |
Dimmed pins aren't populated on the P08 — they belong to the VX, GSR, or H22A looms and stay for the P06/P28/P30 visitors.
Driver round plug
C304 / C126 · driver shock tower · 14-pin
| 1 | BLK/YEL | Alternator feed | Alternator → dash fuse |
| 2 | WHT/BLU | Battery warning light | Gauge cluster ↔ alternator |
| 3 | RED | PCS purge control | A20 |
| 4 | GRN/WHT | IACV | A9 |
| 5 | BLK/YEL | IG1 (key) | Dash fuse 24 → VSS · main relay · ELD |
| 6 | YEL/BLU | VSS | B10 |
| 7 | — | Empty cavity (not used on the EG) | — |
| 8 | YEL/RED | Oil-pressure warning light | Gauge cluster → oil pressure switch |
| 9 | YEL/GRN | FANC | A12 · radiator fan switch |
| 10 | BLK | PG2 power ground | A23 · A24 → G101 · VTP SW |
| 11 | YEL/GRN | Coolant temp sending unit | Gauge cluster |
| 12 | YEL | VTM diff-lock control (auto 4AT only) | Differential lock solenoid |
| 13 | BLU | VTSW diff-lock switch (auto 4AT only) | Differential lock switch |
| 14 | BLU/YEL | VSS B (auto 4AT only) | Transmission speed pickup |
Passenger round plug
C103 / C223 · passenger shock tower · 14-pin
| 1 | WHT/GRN | ALTC | A16 |
| 2 | ORN/BLK | PO2SHTC O2 heater | A6 |
| 3 | GRN/YEL | VTS VTEC solenoid | A4 |
| 4 | GRN/WHT | SG1 to MAP | D21 |
| 5 | WHT/YEL | MAP | D17 |
| 6 | YEL/RED | VCC1 to MAP | D19 |
| 7 | BLU/BLK | VTP SW VTEC pressure | D6 |
| 8 | RED/BLK | TPS | D11 |
| 9 | GRN/BLU | SG2 to O2 | 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 |
Passenger 10-pin
C222 / C102 · distributor pair + O2 · passenger tower
| 1 | BRN/BLK | LG1 / LG2 logic ground | A26 or B2 · thermostat housing |
| 2 | WHT/RED | PHO2S O2 signal | D14 |
| 3 | BRN/BLK | LG1 / LG2 logic ground | 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 (not on P08) |
Injector sub-harness
C221 / C101 · passenger tower · 4-pin
| 1 | RED | INJ2 | A3 |
| 2 | BRN | INJ1 | A1 |
| 3 | YEL | INJ4 | A2 |
| 4 | BLU | INJ3 | A5 |
MAP sensor plug
Firewall · 3-pin
| 1 | WHT | MAP signal | D17 |
| 2 | GRN/WHT (GRN/BLU on D15B7) | SG1 sensor ground | D21 |
| 3 | YEL/RED (YEL/GRN on D15B7) | VCC1 5V supply | D19 |
TPS plug
Throttle body · 3-pin
| 1 | YEL/WHT | VCC2 5V supply | D20 |
| 2 | RED/BLU | TPS signal | D11 |
| 3 | GRN/WHT | SG2 sensor ground | D22 |
Distributor plug
C107 · 8-pin
| 1 | YEL/GRN | ICM | A21 |
| 2 | BLU/GRN | CKP P | B15 |
| 3 | ORN/BLU | TDC P | B13 |
| 4 | ORN | CYP P | B11 |
| 6 | BLU/YEL | CKP M | B16 |
| 7 | WHT/BLU | TDC M | B14 |
| 8 | WHT | CYP M | B12 |
Main relay
Under dash · 7-pin
| 1 | GRN/YEL | FLR1 / FLR2 | A7 · A8 |
| 2 | BLU/WHT | STS starter signal | Under-dash fuse 18 · B9 |
| 3 | BLK | PG1 / PG2 | A23 · A24 · G101 |
| 4 | YEL/GRN | Fuel pump | Under-dash fuse 12 |
| 5 | BLK/YEL | IG1 (key) | — |
| 6 | YEL/BLK | IGP1 / IGP2 | A25 · B1 · injectors · O2 |
| 7 | YEL/WHT | Constant 12V | Under-hood ECU fuse 31 |
VERIFY EVERY PIN AGAINST THE P08 PINOUT CHART BEFORE DEPINNING — REVISION DIFFERENCES EXIST. WIRE COLORS REFERENCE THE STANDARD OBD-1 LOOM.