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 2000–2001 Acura Integra DC2/DB8 uses an OBD2-compliant Engine Control Module (ECM) mounted under the right-side kick panel in the passenger compartment. The ECM governs Honda’s PGM-FI multi-point fuel injection system, controlling fuel injectors, ignition timing, the VTEC solenoid valve, and the idle air control valve whilst monitoring sensors for manifold absolute pressure, intake air temperature, engine coolant temperature, throttle position, and oxygen content. Connector A carries a 32-pin plug, Connector C a 31-pin plug; a 16-pin Data Link Connector (DLC) provides OBD2 scan-tool access. VTEC-equipped variants such as the B18C1 (GSR) include additional ECM pins for the VTEC solenoid valve output and oil pressure switch input.
Connector A
| Pin | name | Signal |
|---|---|---|
| A19 | Engine Speed Pulse | RPM |
| A23 | Secondary O2 Sensor | Analog |
| A32 | Brake Switch | Analog |
Connector B
| Pin | name | Signal |
|---|---|---|
| B10 | Power Ground | Ground |
| B12 | VTEC Solenoid Valve | Analog |
Connector C
| Pin | name | Signal |
|---|---|---|
| C10 | VTEC Pressure Switch | Analog |
| C16 | Primary O2 Sensor | Analog |
| C17 | MAP Sensor | Analog 0.32V @ -13.9 PSI 4.84V @ 10.94 PSI |
| C23 | Vehicle Speed Sensor | Speed |
| C25 | Intake Air Temperature Sensor | Analog |
| C26 | Engine Coolant Temperature Sensor | Analog |
| C27 | Throttle Position Sensor | Analog |
Notes
- ECM connectors are read from the wire side (back of the connector), not the pin face, with the locking tab at the top; this orientation determines the pin numbering sequence.
- The ECM is located under the right-side kick panel on the passenger side, protected by an ECM cover.
- OBD2 diagnostic trouble codes (DTCs) are retrieved via the 16-pin Data Link Connector using a scan tool or Honda PGM Tester; the service check connector used on OBD1 models is not present.
- ECM reset procedure: disconnect the negative battery terminal for at least 30 seconds, or remove the ECM backup fuse. This clears stored DTCs and idle-learn data; an idle relearn procedure is required afterwards.
- The B18C1 engine (Integra GSR/Type R) and B18B1 (LS/RS) share the same physical ECM connector layout but use differently calibrated ECU part numbers.
Signals
- A19 Engine Speed Pulse — RPM signal from the ignition distributor or crankshaft position sensor; used by the ECM to calculate engine speed for fuelling and ignition timing.
- A23 Secondary O2 Sensor — analogue signal from the downstream (post-catalytic converter) heated oxygen sensor; used for OBD2 catalyst efficiency monitoring.
- A32 Brake Switch — analogue input indicating brake pedal application; used by the ECM for idle speed correction and torque converter lock-up control.
- B10 Power Ground — chassis ground reference for the ECM power circuit.
- B12 VTEC Solenoid Valve — ECM output signal controlling the Variable Valve Timing and Lift Electronic Control (VTEC) solenoid valve; activates at a calibrated engine speed threshold to switch cam profiles on VTEC-equipped B-series engines.
- C10 VTEC Pressure Switch — analogue input from the VTEC oil pressure switch; the ECM monitors this to confirm hydraulic pressure is sufficient for VTEC cam engagement.
- C16 Primary O2 Sensor — analogue signal from the upstream (pre-catalytic converter) heated oxygen sensor; primary feedback for closed-loop fuel trim.
- C17 MAP Sensor — analogue manifold absolute pressure signal; the ECM references this for engine load calculation. Typical range: approximately 0.32 V at −13.9 PSI to 4.84 V at +10.94 PSI.
- C23 Vehicle Speed Sensor — speed pulse signal from the vehicle speed sensor; used for idle speed control, fuel cut strategy, and speedometer output.
- C25 Intake Air Temperature Sensor — analogue input from the IAT sensor in the intake tract; used for air density correction of the fuel injection map.
- C26 Engine Coolant Temperature Sensor — analogue input from the ECT sensor; governs cold-start enrichment, cooling fan control, and warm-up ignition advance.
- C27 Throttle Position Sensor — analogue voltage input proportional to throttle plate angle; used for acceleration enrichment and deceleration fuel cut.