What do you mean pcm is in the car?

Pcm is the engine control module. PCM will receive sensor signals, and control the adjustment of fuel supply, air distribution (electronic throttle), fuel injection and ignition timing, intake pressure according to temperature, load, knocking and combustion conditions, and determine the compensation control coefficient of the engine.

Automobi le EngineControlModule is the core component of engine control. It controls the fuel injection and ignition timing of the engine according to the input information of each sensor, and provides the best control instructions for other output devices. In addition, ECM also detects its own faults, sensors and actuators, serial data lines and MIL circuits. When a fault is detected, the ECM will remember the corresponding fault code and take corresponding measures. The calibration program of engine control is stored in EEPROM, which is a permanent memory welded to ECM and cannot be replaced separately. When replacing the ECM, the new ECM must be programmed according to the configured vehicle model before it can be used.

Engine control module can provide 5V or 12V voltage to each sensor or switch, which is realized by adjusting power supply to the engine control module through feedback resistor. In some cases, the ordinary voltmeter used in the repair shop will lead to inaccurate reading because of its low impedance. Therefore, it is required to use a digital multimeter with an input impedance of at least 10MQ to ensure accurate voltage reading. (Photo/Text/Photo: Zeng Huiwen) @20 19