The ECU (Engine Control Unit) on the 1991–1993 Nissan Silvia S13 fitted with the SR20DET engine manages the Nissan ECCS (Electronic Concentrated Control System), which provides sequential multi-point fuel injection and electronic ignition timing control. The SR20DET is a 2.0 litre twin-cam turbocharged four-cylinder engine introduced in the S13 RWD Silvia and 180SX from 1991. Like other S-chassis Nissans of the period, the ECU uses a multi-pin Nissan-proprietary connector and communicates with external diagnostic equipment via a 14-pin CONSULT serial interface port.
ECU - Electronic Control Unit Connector.
| Pin | name | Signal |
|---|---|---|
| 3 | Tachometer Signal | RPM |
| 13 | Power Ground (Electronic Concentrated Control System) | Ground |
| 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 |
| 26 | Air Temperature Sensor | Analog |
| 32 | Vehicle Speed Sensor | Speed |
| 39 | Power Ground (Electronic Concentrated Control System) | Ground |
| 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 S13 SR20DET ECU connector is a Nissan-proprietary multi-pin unit; S-chassis ECUs of this era use a 76-pin or 64-pin connector depending on variant. The injector drive signals listed (pins 101–116 range) are active-low outputs. Multiple dedicated ground pins are provided: pins 13 and 39 are power grounds for the ECCS system, while pin 21 is the sensor signal ground. The vehicle speed sensor signal (pin 32) is a digital pulse output.
Signals
- Tachometer Signal — engine speed output to the instrument cluster, derived from ignition events; units RPM
- Power Ground (ECCS) — chassis/power ground reference for the Electronic Concentrated Control System (pins 13, 39, 116)
- Mass Air Flow Sensor — analogue voltage from the hot-wire MAF sensor indicating intake air mass
- Mass Air Flow Sensor Ground — dedicated ground return for the MAF sensor circuit
- Engine Coolant Temperature Sensor — analogue NTC thermistor signal used for fuel and timing corrections
- O2 Sensor Signal — analogue voltage from the exhaust oxygen sensor for closed-loop fuelling
- Throttle Position Sensor — analogue voltage indicating throttle plate angle; used for load calculation and acceleration enrichment
- Sensor Ground — common signal ground for analogue sensor returns
- Air Temperature Sensor — analogue NTC thermistor signal for intake air temperature compensation
- Vehicle Speed Sensor — digital pulse signal proportional to road speed; used for idle-up and fuel cut logic
- Injector #1 / #2 / #3 / #4 — low-side injector drive signals for sequential multi-point injection; signal type listed as Speed in source data; function unknown beyond injector activation