ECU - Electronic Control Unit Connector.
The 1997 Acura 2.2 CL uses Honda’s PGM-FI (Programmed Fuel Injection) engine management system, sharing its F22B2 2.2-litre SOHC VTEC engine and ECM architecture with the contemporary Honda Accord CD-series. As an OBD2-compliant model year 1997 vehicle, the ECM communicates via a 16-pin Data Link Connector (DLC) conforming to SAE J1962 for diagnostic scan tool access. The ECM is mounted in the passenger compartment and uses lettered multi-pin connector blocks (A, C, D) to interface with engine sensors, actuators, and the vehicle wiring harness.
Connector A
| Pin | name | Signal |
|---|---|---|
| A8 | VTEC Solenoid Valve | Analog |
| A10 | Power Ground | Ground |
| A20 | Ignition Control Module | RPM |
| A23 | Power Ground | Ground |
Connector C
| Pin | name | Signal |
|---|---|---|
| C15 | VTEC Pressure Switch | Analog |
| C18 | Vehicle Speed Sensor | Speed |
Connector D
| Pin | name | Signal |
|---|---|---|
| D1 | Throttle Position Sensor | Analog |
| D2 | Engine Coolant Temperature Sensor | Analog |
| D3 | MAP Sensor | Analog 0.32V @ -13.9 PSI 4.84V @ 10.94 PSI |
| D5 | Brake Switch | Analog |
| D7 | Primary O2 Sensor | Analog |
| D8 | Intake Air Temperature Sensor | Analog |
| D14 | Secondary O2 Sensor | Analog |
Notes
ECM connectors are read from the wire side (rear of the connector housing), with the locking tab oriented at the top; this convention determines the pin numbering direction. To reset stored DTCs, disconnect the negative battery terminal for at least 30 seconds or remove the ECM backup fuse; note that this also clears idle learn data, requiring an idle relearn procedure afterwards. The VTEC solenoid valve (A8) and VTEC oil pressure switch (C15) are present because the F22B2 engine is VTEC-equipped. The MAP sensor voltage on D3 varies linearly with manifold absolute pressure between the reference values shown.
Signals
- A8 — VTEC Solenoid Valve — ECM-controlled output that engages the VTEC variable valve-timing mechanism at the programmed RPM and load threshold.
- A10 — Power Ground — chassis/power ground reference for ECM output circuits.
- A20 — Ignition Control Module — RPM signal output from the ECM to the ignition control module governing ignition timing.
- A23 — Power Ground — additional chassis/power ground reference.
- C15 — VTEC Pressure Switch — input from the VTEC oil pressure switch confirming hydraulic pressure when the VTEC solenoid has engaged.
- C18 — Vehicle Speed Sensor — pulse input from the vehicle speed sensor used by the ECM for speed-dependent fuelling and idle control.
- D1 — Throttle Position Sensor — analogue voltage input indicating throttle plate angle.
- D2 — Engine Coolant Temperature Sensor — analogue voltage input used by the ECM for cold-start enrichment and cooling fan control.
- D3 — MAP Sensor — analogue voltage input from the manifold absolute pressure sensor (0.32 V at −13.9 PSI; 4.84 V at 10.94 PSI); primary load signal for fuel and ignition calculations.
- D5 — Brake Switch — input signal indicating brake pedal application; used for torque converter lock-up control on automatic transmission variants.
- D7 — Primary O2 Sensor — upstream heated oxygen sensor input used for closed-loop fuelling correction.
- D8 — Intake Air Temperature Sensor — analogue voltage input used for air-density correction of fuel delivery.
- D14 — Secondary O2 Sensor — downstream oxygen sensor input used for catalyst efficiency monitoring (OBD2 readiness monitor).