ECU - Electronic Control Unit Connector.
The 1988–1991 Nissan Silvia S13 fitted with the CA18DET engine uses a 76-pin ECU connector as part of Nissan’s ECCS (Electronic Concentrated Control System). ECCS provides sequential multi-point fuel injection and electronic ignition timing control from a single Engine Control Module. The CA18DET is a 1.8-litre turbocharged DOHC inline-four, and its ECU is documented in the Nissan S13 factory service manual under section EF & EC (Engine Fuel & Emission Control System). A 14-pin CONSULT data-link connector connects the ECM to Nissan’s serial diagnostic interface for fault retrieval and real-time monitoring.
Connector A
| Pin | name | Signal |
|---|---|---|
| 7 | Tachometer Signal | RPM |
| 26 | Mass Air Flow Sensor Ground | Ground |
| 27 | Mass Air Flow Sensor | Analog |
| 28 | Engine Coolant Temperature Sensor | Analog |
| 29 | O2 Sensor Signal | Analog |
| 30 | Sensor Ground | Ground |
| 38 | Throttle Position Sensor | Analog |
| 50 | Power Ground (Engine Control Module) | Ground |
| 53 | Vehicle Speed Sensor | Speed |
| 101 | Injector # 1 | Speed |
| 103 | Injector # 3 | Speed |
| 110 | Injector # 2 | Speed |
| 112 | Injector # 4 | Speed |
| 116 | Power Ground (Engine Control Module) | Ground |
Notes
The ECU connector is a 76-pin Nissan-proprietary unit. Only a subset of pins are listed here; remaining positions carry ignition control, idle-air control, fuel-pump relay, and CONSULT serial communication signals not shown in this partial table.
Signals
- Tachometer Signal — engine speed output from the ECM to the instrument cluster tachometer, in RPM
- Mass Air Flow Sensor Ground — dedicated analogue ground return for the MAF sensor circuit
- Mass Air Flow Sensor — analogue voltage signal from the hot-wire mass air flow sensor; used by ECCS to calculate injector pulse width
- Engine Coolant Temperature Sensor — analogue signal from the coolant temperature thermistor; used for cold-start enrichment and ignition advance correction
- O2 Sensor Signal — analogue voltage from the upstream exhaust oxygen sensor; used for closed-loop fuel trim
- Sensor Ground — common analogue ground for sensor reference circuits
- Throttle Position Sensor — analogue voltage indicating throttle plate angle; used for acceleration enrichment and idle detection
- Power Ground (Engine Control Module) — high-current chassis ground for the ECM power stage (pin 50)
- Vehicle Speed Sensor — pulse signal from the transmission speed sensor used for fuel cut, idle-up, and speedometer drive
- Injector #1 — low-side driver output to fuel injector cylinder 1
- Injector #3 — low-side driver output to fuel injector cylinder 3
- Injector #2 — low-side driver output to fuel injector cylinder 2
- Injector #4 — low-side driver output to fuel injector cylinder 4
- Power Ground (Engine Control Module) — high-current chassis ground for the ECM power stage (pin 116)