The 1995–1996 Nissan Altima uses the KA24DE 2.4-litre DOHC inline-four engine managed by Nissan’s ECCS (Electronic Concentrated Control System), which provides sequential multi-point fuel injection and electronic ignition timing control from a single ECM. From 1995 onwards, US-market Altimas comply with OBD-II emissions diagnostics, accessed through a standardised 16-pin data link connector. The 1996 California-emissions variant is excluded from this connector mapping due to differences in the exhaust-aftertreatment monitoring circuitry. The ECM communicates with the Nissan CONSULT serial diagnostic interface via dedicated signal lines in the engine harness.
ECU - Electronic Control Unit Connector.
| 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
This pinout covers the non-California 1995 and 1996 Altima only; the 1996 California-emissions model uses different O2 sensor monitoring and is excluded. Pin 33 (Throttle Position Sensor, A/T) is present on automatic-transmission variants only. Pins 112 and 118 both carry power ground for the ECCS system and are chassis-grounded at the ECM mounting point.
Signals
- Tachometer Signal — engine speed output from the ECM to the instrument cluster, derived from crankshaft position sensor data
- Throttle Position Sensor — analogue voltage from the TPS indicating throttle plate angle; used for load calculation and transient fuel enrichment
- Vehicle Speed Sensor — pulse signal indicating road speed; used for fuel cut, idle control, and speedometer drive
- Throttle Position Sensor (A/T) — second TPS input used by the ECM on automatic-transmission models for shift-point and torque-converter lock-up control
- O2 Sensor Signal (Front) — analogue voltage from the upstream (pre-catalyst) heated oxygen sensor; primary fuel-trim feedback signal
- Mass Air Flow Sensor — analogue voltage from the hot-wire MAF sensor proportional to intake air mass
- Mass Air Flow Sensor Ground — dedicated signal ground for the MAF sensor circuit
- Sensor Ground — common reference ground for analogue sensor signals (TPS, coolant temp, intake air temp)
- Engine Coolant Temperature Sensor — analogue voltage inversely proportional to coolant temperature; used for cold-start enrichment and fan control
- O2 Sensor Signal (Rear) — analogue voltage from the downstream (post-catalyst) heated oxygen sensor; used for catalyst efficiency monitoring under OBD-II
- Intake Air Temperature Sensor — analogue voltage inversely proportional to intake air temperature; used for air-density correction of fuelling
- Power Supply (Aux) — auxiliary battery-backed power feed to the ECM, maintaining memory for adaptive fuel-trim and fault codes
- Injector #1 — low-side drive signal to fuel injector on cylinder 1
- Injector #3 — low-side drive signal to fuel injector on cylinder 3
- Injector #2 — low-side drive signal to fuel injector on cylinder 2
- Injector #4 — low-side drive signal to fuel injector on cylinder 4
- Power Ground (ECCS) — main power ground return for the ECCS control system (pin 112)
- Power Ground (ECCS) — second main power ground return for the ECCS control system (pin 118)