The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. The skid control ECU converts these wheel speed signals into a pulse signal and outputs it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency of this pulse signal.

To reduce hydrocarbon emissions, evaporated fuel from the fuel tank is routed through a charcoal canister to the intake manifold for combustion in the cylinders.

The ECM changes the duty signal sent to the purge VSV (Vacuum Switching Valve for Purge Control) so that the intake amount of hydrocarbon emissions is appropriate for the driving conditions (engine load, engine speed, vehicle speed, etc.) after the engine is warmed up.

The ECM uses sensors mounted in front of and behind the Three-way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the air fuel ratio sensor, sends pre-catalyst information to the ECM. The second sensor, the heated oxygen sensor, sends post-catalyst information to the ECM.

In the VVT (Variable Valve Timing) system, the appropriate intake and exhaust valve open and close timing is controlled by the ECM. The ECM performs intake and exhaust valve control by performing the following: 1) controlling the camshaft and camshaft timing oil control valve, and operating the camshaft timing gear; and 2) changing the relative positions of the camshaft and crankshaft.

Refer to DTC P0412 ().

The ECM operates the air injection VSV relay (AI-VSV) which causes the air switching valve (for bank 2) to operate.

The secondary air injection system injects air into the exhaust port of the cylinder head using an electric air pump, starting when the engine is started cold and operating until the catalyst warms up, in order to promote combustion of unburned fuel and decrease the amount of hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas.

Refer to DTC P0013 ().

These DTCs are designed to detect opens or shorts in the camshaft timing oil control valve circuit. If the camshaft timing oil control valve duty cycle is excessively high or low while the engine is running, the ECM will illuminate the MIL and store the DTC.

The monitor for this DTC runs 5 seconds after the engine switch is turned on (IG).

The exhaust camshaft VVT sensor (EV1 and EV2 signals) consists of a magnet and MRE (Magnetoresistive Element).