ECU - Electronic Control Unit Connector.
The Nissan S14 Silvia, produced from 1993 to 1998, was sold in European markets with the SR20DET engine — a 2.0 litre DOHC turbocharged inline-four using Nissan’s ECCS (Electronic Concentrated Control System) for sequential multi-point fuel injection and electronic ignition timing. The ECU is a multi-pin unit that manages injector drive signals, sensor inputs (mass airflow, throttle position, coolant temperature, and oxygen sensor), and power/ground distribution. The European-specification variant shares the core ECM connector layout with the JDM S14 SR20DET but may differ in oxygen sensor and catalyst-monitor wiring to meet European emissions requirements. The S14 was produced in Zenki (1993–1996) and Kouki (1997–1998) forms, both using the SR20DET with ECCS management.
| Pin | name | Signal |
|---|---|---|
| 2 | Tachometer Signal | RPM |
| 16 | Mass Air Flow Sensor | Analog |
| 17 | Mass Air Flow Sensor Ground | Ground |
| 18 | Engine Coolant Temperature Sensor | Analog |
| 19 | O2 Sensor Signal | Analog |
| 20 | Throttle Position Sensor | Analog |
| 21 | Sensor Ground | Ground |
| 29 | Sensor Ground | Ground |
| 32 | Vehicle Speed Sensor | Speed |
| 101 | Injector # 1 | Speed |
| 103 | Injector # 3 | Speed |
| 110 | Injector # 2 | Speed |
| 112 | Injector # 4 | Speed |
| 116 | Power Ground (Electronic Concentrated Control System) | Ground |
Notes
The ECU connector follows Nissan’s multi-pin header arrangement used across the S-chassis SR20DET family. The injector drive signal columns are labelled “Speed” in this table, which reflects the original page encoding; the signals are PWM injector drive outputs, not speed signals. The European-specification S14 may include additional oxygen sensor or catalyst-monitor wiring not listed here. Diagnostics are accessed via the Nissan CONSULT serial interface, which connects to the ECM through a dedicated data-link connector exposing CHK, IGN, RX, and TX lines.
Signals
- Tachometer Signal — engine speed output from the ECM to the instrument cluster, derived from crank position sensing.
- Mass Air Flow Sensor — analogue voltage signal from the hot-wire MAF sensor; used by the ECM to calculate intake air mass for fuel delivery calculation.
- Mass Air Flow Sensor Ground — dedicated return ground for the MAF sensor circuit.
- Engine Coolant Temperature Sensor — analogue NTC thermistor signal; used by the ECM to apply cold-start enrichment and ignition timing corrections.
- O2 Sensor Signal — analogue voltage from the upstream lambda (oxygen) sensor; used for closed-loop fuelling correction.
- Throttle Position Sensor — analogue voltage proportional to throttle plate angle; used for load determination and transient fuelling.
- Sensor Ground (pins 21 and 29) — dedicated low-noise ground reference for analogue sensor circuits.
- Vehicle Speed Sensor — pulse signal from the transmission-mounted speed sensor; used for idle-up control and speed-dependent functions.
- Injector #1, #2, #3, #4 — sequential injector drive outputs; the ECM grounds each injector in firing-order sequence. Pin 101 drives cylinder 1, pin 103 cylinder 3, pin 110 cylinder 2, and pin 112 cylinder 4.
- Power Ground (ECCS) — main power ground for the ECM and ECCS system, connected directly to chassis earth.