ECU - Electronic Control Unit Connector.
The 1995–1997 Nissan Sentra (B13/N14 platform, excluding the 1997 1.6 L variant) uses Nissan’s ECCS (Electronic Concentrated Control System) engine management, which provides sequential multi-point fuel injection and electronic ignition timing from a single ECM. The engines covered include the GA16DE (1.6 L DOHC, early years) and SR20DE (2.0 L DOHC naturally aspirated). The ECM uses a multi-pin connector with terminals numbered into the triple digits, consistent with the B13/N14 family wiring architecture documented in the official Nissan factory workshop manual.
| Pin | name | Signal |
|---|---|---|
| 3 | Tachometer Signal | RPM |
| 23 | Throttle Position Sensor | Analog |
| 26 | Vehicle Speed Sensor | Speed |
| 33 | Throttle Position Sensor (A/T) | 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 |
| 63 | Intake Air Temperature Sensor | Analog |
| 70 | Power Supply (Aux) | Power |
| 102 | Injector # 1 | Speed |
| 104 | Injector # 3 | Speed |
| 107 | Injector # 2 | Speed |
| 109 | Injector # 4 | Speed |
| 112 | Power Ground (Electronic Concentrated Control System) | Ground |
| 118 | Power Ground (Electronic Concentrated Control System) | Ground |
Notes
The connector covers only the pins listed; remaining terminals in the ECM header serve functions not tabulated here. Pin 33 (Throttle Position Sensor A/T) is present only on automatic transmission variants. The 1997 1.6 L model is excluded and uses a different ECM connector arrangement. The ECM is accessible via Nissan’s CONSULT serial diagnostic interface. Only a subset of the full ECM connector is shown above.
Signals
- Tachometer Signal — engine speed output from the ECM to the instrument cluster tachometer
- Throttle Position Sensor — analogue voltage from the throttle position sensor; rises with throttle opening
- Vehicle Speed Sensor — pulsed signal proportional to road speed, used for idle-up and fuel cut control
- Throttle Position Sensor (A/T) — throttle position input used by the automatic transmission control logic; absent on manual transmission models
- O2 Sensor Signal (Front) — analogue voltage from the upstream (pre-catalyst) heated oxygen sensor for closed-loop fuel trim
- Mass Air Flow Sensor — analogue voltage from the hot-wire MAF sensor; primary load input to the ECCS
- Mass Air Flow Sensor Ground — dedicated signal ground return for the MAF sensor
- Sensor Ground — common low-noise ground reference for analogue sensor inputs
- Engine Coolant Temperature Sensor — analogue voltage from the coolant temperature thermistor; used for cold-start enrichment and fan control
- O2 Sensor Signal (Rear) — analogue voltage from the downstream (post-catalyst) oxygen sensor for catalyst efficiency monitoring
- Intake Air Temperature Sensor — analogue voltage from the inlet air temperature thermistor; used to correct fuel delivery for air density
- Power Supply (Aux) — auxiliary battery-backed power supply to retain ECM memory and adaptive fuel trim values
- Injector #1 — drive signal for cylinder 1 fuel injector (peak-and-hold saturated drive)
- Injector #3 — drive signal for cylinder 3 fuel injector
- Injector #2 — drive signal for cylinder 2 fuel injector
- Injector #4 — drive signal for cylinder 4 fuel injector
- Power Ground (ECCS) — main power ground for the Electronic Concentrated Control System ECM (pin 112)
- Power Ground (ECCS) — second main power ground for the ECM (pin 118); redundant ground path for noise reduction