The computer is divided into 2 modules. The logic module contains the operating software and performs the calculations and adjustments necessary for engine operation. This half of the computer is located inside the passenger compartment behind the right front kick panel.

The logic module is a microprocessor based digital computer. This module receives input signals from various switches, sensors, and other components. Using these signals, the microprocessor computes the fuel injector pulse width, spark advance, ignition coil dwell, automatic idle speed actuation, canister purge, and EGR control solenoid cycles.

The logic module also contains a diagnostic circuit to test input and output circuits. The diagnostic circuit will store information about any malfunctions as they occur for readout prior to service.

The second part of the computer is the power module. The power module contains a voltage converter which maintains the power supply at 8 volts. The module controls the circuits for the fuel injector, the ignition system, and the automatic shutdown relay.

The power module is located in the engine compartment because the high current draw of the devices being controlled can cause electrical noise which must be isolated from the logic module. The power module is controlled by the logic module.

Fig 1: Location of Logic Module, Sensor & Relay

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

2.2L EFI CEC System: Operation: Computer

Use the Manual With the Right Hardware

When to See a Mechanic