This DTC is stored when a communication error occurs in the ECM.

The main CPU and sub CPU of the ECM perform data communication between each other. The main CPU monitors the communications and WDC pulses from the sub CPU. When the signal malfunctions below are detected, this DTC is stored.

The ECM continuously monitors its main and sub CPUs. This self-check ensures that the ECM is functioning properly. If outputs from the CPUs are different and deviate from the standard, the ECM will illuminate the MIL and store a DTC immediately.

The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM stores the appropriate DTC and illuminates the MIL.

The battery supplies electricity to the ECM even when the ignition switch is off. This power source allows the ECM to store data such as DTC history, freeze frame data and fuel trim values. If the battery voltage falls below a minimum level, the memory is cleared and the ECM determines that there is a malfunction in the power supply circuit. When the engine is next started, the ECM illuminates the MIL and stores the DTC.

Refer to DTC P2195 ().

The power steering oil pressure sensor is turned on when a power steering wheel load is generated by turning the steering wheel. The ECM regulates the engine idling speed according to the voltage output of the sensor.

In the VVT (Variable Valve Timing) system, the appropriate exhaust valve open and close timing is controlled by the ECM. The ECM performs 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.

The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If signals which indicate the brake pedal is being depressed and released are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and stores the DTC.

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.