ECU - Electronic Control Unit Connector.
The 2003 Mitsubishi Lancer Evolution VIII (chassis code CT9A) uses a Mitsubishi-proprietary engine control unit to manage the turbocharged 4G63T 2.0 L DOHC four-cylinder engine. Unlike the naturally aspirated Lancer variants of the same era, the Evo 8 ECU integrates boost control and all-wheel-drive management, giving it a distinct connector pinout not shared with Eclipse or standard Lancer units. The ECU’s terminal inspection procedures are documented in the 2003 Lancer Evolution VIII Workshop Manual, which provides reference voltage and signal condition data for each circuit.
| Pin | name | Signal |
|---|---|---|
| 26 | Power Ground | Ground |
| 72 | Intake Air Temperature Sensor | Analog |
| 75 | Secondary O2 Sensor | Analog |
| 76 | Primary O2 Sensor | Analog |
| 83 | Engine Coolant Temperature Sensor | Analog |
| 84 | Throttle Position Sensor | Analog |
| 86 | Vehicle Speed Sensor | Speed |
| 90 | Mass Air Flow | Analog |
Notes
The Evo 8 ECU connector is a Mitsubishi-proprietary multi-pin unit; pin numbers in this table correspond to the terminal numbering used in the factory workshop manual terminal inspection charts. Only a subset of terminals is listed here. The ECU is located within the passenger compartment on the CT9A chassis.
Signals
- Power Ground — chassis ground return for the ECU power supply circuit (pin 26).
- Intake Air Temperature Sensor — analogue signal from the IAT sensor; used by the ECU to calculate air density for fuel and boost corrections.
- Secondary O2 Sensor — analogue signal from the downstream (post-catalytic converter) oxygen sensor; used for catalyst monitoring.
- Primary O2 Sensor — analogue signal from the upstream (pre-catalyst) oxygen sensor; primary input for closed-loop fuelling control.
- Engine Coolant Temperature Sensor — analogue signal from the ECT sensor; influences fuelling enrichment, idle speed, and radiator fan control.
- Throttle Position Sensor — analogue voltage signal indicating throttle plate angle; used for load calculation and acceleration enrichment.
- Vehicle Speed Sensor — pulse signal from the transmission output shaft speed sensor; used for speed-dependent idle and AWD control functions.
- Mass Air Flow — analogue signal from the hot-wire MAF sensor; primary airflow measurement for the MPI fuel injection calculation.