| Pin | Wire Color | Signal | Description | |-----|------------|--------|--------------| | B1 | B-W | M-REL | Main relay control (ECU triggers relay) | | B2 | L | FAN | Radiator fan relay control | | B3 | G-R | EGR | EGR vacuum switching valve (VSV) | | B4 | R | VSV1 | Fuel pressure VSV (spill control valve) | | B5 | B-Y | VCV | Spill control valve (fuel pump) | | B6 | L-R | TCV | Timing control valve (injection timing) | | B7 | Y | EDU | Injector driver ground (to EDU – early models) | | B8 | W | EDU+ | Injector driver power (to EDU) | | B9 | B-O | ELS | Electrical load signal (from alternator) | | B10 | G | SPD | Vehicle speed sensor (from combination meter) | | B11 | W-B | W | Check engine light (warning lamp) | | B12 | R-B | TACH | Tachometer output | | B13 | G-B | FPR | Fuel pump relay (lift pump – some models) | | B14 | L-B | STP | Stop light switch (brake input) | | B15 | R-W | +BM | Backup power for ECU memory (constant +12V) | | B16 | B | E01 | Power ground (injector driver) |
Inspect the wiring harness routing near the bottom of the injection pump. The wires leading to the TCV frequently become brittle from engine heat, oil saturation, and vibration. 1kz ecu pinout
Neutral Start Switch input, preventing starting unless in Park or Neutral. | Pin | Wire Color | Signal |
A common issue with aging 1990s Toyota ECUs is leaking electrolytic capacitors. If you experience random stalling, intermittent check engine lights, or unexplained sensor codes, open the ECU casing and look for leaking fluid or corroded circuit board traces. A common issue with aging 1990s Toyota ECUs
Wire IGSW to your ignition key switch "ON" position.