What Causes the Dashboard Key Light to Flash and the Car Not to Start?
1 Answers
There are generally two common reasons for this situation: 1. Insufficient battery power: (1) Modern car engines are electronically controlled fuel injection systems, operated by the engine control unit (ECU), which itself consumes power. When the key is turned, the main relay engages to supply power to the ECU, which then begins operation. (2) During ignition, the starter motor requires a large amount of power, drawing a significant current at startup. This causes a substantial drop in battery voltage, leading the main relay to disconnect due to the low voltage, causing the ECU to shut down. (3) When the key is released, the battery voltage returns to normal, the relay re-engages, and the ECU restarts. This can result in the dashboard needles swinging violently and indicator lights flashing, accompanied by the clicking sound of the relay. 2. Poor electrical contact: The principle is similar to the above, where the starter motor's high current causes a poor contact point to break the circuit, disconnecting the relay. When the key is released, the current decreases, and the poor contact point re-establishes the connection. A common example is severe corrosion at the battery terminals, reducing the effective contact area. This can be resolved by removing and cleaning the terminals.
