The ECU - Electronic Control Unit for the 1997–1999 Nissan Sentra B14 (excluding the 1997 2.0 L SR20DE model) uses Nissan’s ECCS (Electronic Concentrated Control System) multi-point sequential fuel injection. The ECM manages fuelling, ignition timing, idle speed, and emissions functions via a multi-pin connector. This page covers the 1.6 L GA16DE variant, which shares the B13/B14 platform ECM architecture documented in the Nissan factory workshop manual for the Sentra, Sunny, and related N14 models.
ECU - Electronic Control Unit Connector.
| Pin | name | Signal |
|---|---|---|
| 3 | Tachometer Signal | RPM |
| 23 | Throttle Position Sensor | Analog |
| 26 | Vehicle Speed Sensor | Speed |
| 28 | Intake Air Temperature Sensor | Analog |
| 46 | O2 Sensor Signal (Front) | Analog |
| 47 | Mass Air Flow Sensor | Analog |
| 48 | Mass Air Flow Sensor Ground | Ground |
| 50 | Sensor Ground | Ground |
| 51 | Engine Coolant Temperature Sensor | Analog |
| 52 | O2 Sensor Signal (Rear) | Analog |
| 102 | Injector # 1 | Speed |
| 104 | Injector # 3 | Speed |
| 107 | Injector # 2 | Speed |
| 109 | Injector # 4 | Speed |
| 118 | Power Ground (Electronic Concentrated Control System) | Ground |
Notes
The 1997 2.0 L SR20DE-equipped Sentra uses a different ECM connector arrangement and is excluded from this pinout. Only selected pins relevant to sensor and injector circuits are listed here; the full ECM connector contains additional terminals for ignition, idle air control, evaporative emissions, and CONSULT diagnostic interface signals. Injector signal entries are labelled “Speed” in the source table; this reflects the column classification used in the original data, not a signal type — injector drive signals are switched ground outputs.
Signals
- Tachometer Signal — engine speed output from the ECM to the instrument cluster tachometer (RPM)
- Throttle Position Sensor — analogue voltage signal indicating throttle plate angle; used for fuel and ignition calculations
- Vehicle Speed Sensor — pulse signal representing road speed; used for idle-up control and ECCS functions
- Intake Air Temperature Sensor — analogue voltage from the IAT sensor; used to correct fuel delivery for air density
- O2 Sensor Signal (Front) — analogue voltage from the upstream (pre-catalyst) heated oxygen sensor; primary lambda feedback
- Mass Air Flow Sensor — analogue voltage from the hot-wire MAF sensor measuring intake air mass
- Mass Air Flow Sensor Ground — dedicated signal ground for the MAF sensor
- Sensor Ground — common reference ground for analogue sensor circuits
- Engine Coolant Temperature Sensor — analogue voltage from the ECT sensor; used for cold-start enrichment and cooling fan control
- O2 Sensor Signal (Rear) — analogue voltage from the downstream (post-catalyst) oxygen sensor; used for catalyst monitoring
- Injector #1 — injector drive output for cylinder 1
- Injector #3 — injector drive output for cylinder 3
- Injector #2 — injector drive output for cylinder 2
- Injector #4 — injector drive output for cylinder 4
- Power Ground (Electronic Concentrated Control System) — main ECM power ground return