The ECU - Electronic Control Unit is an embedded system that controls one or more of the electrical systems or subsystems in a vehicle.
ECU - Electronic Control Unit Connector.
The 1997–1999 Nissan 200SX (B14 chassis, excluding the 1997 2.0 L SR20DE variant) is fitted with the GA16DE 1.6 L DOHC naturally aspirated four-cylinder engine managed by Nissan’s ECCS (Electronic Concentrated Control System). The ECU is a multi-pin unit providing sequential multi-point fuel injection and electronic ignition timing control on the OBD-II-compliant platform introduced for the 1996 model year. Sensor inputs include a mass air flow sensor, throttle position sensor, intake air temperature sensor, and coolant temperature sensor, while front and rear heated oxygen sensors support closed-loop fuel trim and catalytic converter monitoring. Injector drive signals are sourced directly from the ECU, with a dedicated power ground routed through the ECCS earth circuit.
| 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
This pinout covers the GA16DE (1.6 L) variant only; the 1997 SR20DE (2.0 L) version uses a different ECU connector layout and is excluded. The 1997–1999 200SX is OBD-II compliant; diagnostic access is via the standardised 16-pin DLC located under the dashboard, not the earlier Nissan CONSULT 14-pin port.
Signals
- Tachometer Signal — engine speed output from the ECU to the instrument cluster tachometer, in revolutions per minute
- Throttle Position Sensor — analogue voltage signal indicating throttle plate angle; used for load calculation, idle detection, and acceleration enrichment
- Vehicle Speed Sensor — speed pulse signal from the transmission; used for idle-up control and torque converter lock-up logic
- Intake Air Temperature Sensor — analogue signal from the IAT sensor (integral to the MAF housing on GA16DE); used to correct fuel delivery for inlet air density
- O2 Sensor Signal (Front) — analogue voltage from the upstream (pre-cat) heated oxygen sensor; used for closed-loop fuel trim
- O2 Sensor Signal (Rear) — analogue voltage from the downstream (post-cat) oxygen sensor; used for catalytic converter efficiency monitoring under OBD-II
- Mass Air Flow Sensor — analogue voltage from the hot-wire MAF sensor; primary engine load input to the ECCS fuel calculation
- Mass Air Flow Sensor Ground — dedicated signal ground for the MAF sensor circuit
- Sensor Ground — common analogue ground reference for temperature and pressure sensors
- Engine Coolant Temperature Sensor — analogue signal from the ECT sensor; used for cold-start enrichment, fan control, and idle speed correction
- Injector #1 / #2 / #3 / #4 — sequential injector drive outputs; each cylinder injector is driven independently by the ECU
- Power Ground (Electronic Concentrated Control System) — main ECCS power earth; connects the ECU to chassis ground via the dedicated ECCS earth point