ND5 — NineDFive.OnlineD15B 2008366
Hank the robot mechanic proudly holding a freshly tucked D15B engine harness, connectors fanned out

GARAGE REFERENCE // PRINTABLE

Harness & Vacuum Map.

The whole nervous system on one page: power in, every ECU branch to its destination, and every vacuum line from source to service. The final sheet in the garage print set.

D15B — Electrical & Vacuum Schematic Wiring Vacuum
HARNESS ROUTE — KICK PANEL → FIREWALL → SHOCK TOWERP08 ECUA / B / D plugsMAIN RELAYPGM-FI · powers ECU + pumpUNDER-HOOD FUSE BOXbattery · always-on 12VG101 MAIN GROUND — THERMOSTAT HOUSING STUDSHOCK-TOWER PLUGSfirewall junctionINJECTORS ×4peak-and-hold — A1/A2/A3/A5RESISTOR BOXinjector current limiterDISTRIBUTOR 8-PINCYP/TDC/CKP — B11–B16VTEC SPOOL VALVEsolenoid A4 · switch D6HEATED O2 SENSORsignal D14 · heater A6ECT · TPS · MAP · IATD-plug analog inputsIACVidle air control — throttle bodyVSS · KNOCK SENSORspeed signal · JDM knockNOTES — OBD-1 LOOM· INJECTOR + O2 HEATER 12V: SWITCHED FROM MAIN RELAY· SENSOR GROUNDS RETURN TO THE ECU — NEVER CHASSIS-GROUND· NO VTEC AT 4,600? CHECK OIL + PRESSURE SWITCH FIRSTVACUUM MAP — ALL LINES FROM INTAKE MANIFOLDINTAKE MANIFOLDD15B P08 plenumMAP SENSORthrottle body portFUEL PRESSURE REG.3.5 mm signal lineEVAP PURGE VALVEmanifold signalCHARCOAL CANISTERstores fuel vaporPCV VALVEvalve cover → manifoldBRAKE BOOSTER10 mm + check valveCHECK VALVE ARROW POINTS TOWARD BOOSTER — TEST: BLOW TOWARD BOOSTER ONLY

Golden Rule

Clean G101 at the thermostat housing before diagnosing anything. Half of all D15B electrical gremlins are that one ground.

Vacuum Rule

Replace hoses one at a time against the under-hood label. A 1 mm leak at the FPR line raises fuel pressure and washes the rings.

Cross-Reference

Pin-level detail lives on the P08 Pinout Card; live diagnosis starts at the Fault-Code Decoder on Specs/Guides.

SCHEMATIC IS SIMPLIFIED FOR BENCH USE. WIRE COLORS AND PIN NUMBERS REFERENCE THE STANDARD OBD-1 LOOM — VERIFY AGAINST THE P08 PINOUT CHART.