DC-DC CONVERTER
id119000000400
Purpose of Adoption
• A DC-DC converter has been adopted. When the engine is restarted by the i-stop control, the battery voltage temporarily decreases to operate the starter, however, it increases to maintain voltage for the vehicle's electrical devices.
Service Point
• Insert the DC-DC converter connector straight and completely, operate the connector lever until a click sound is heard (locked), and securely fix it.
• Measure the gravity of the battery fluid using a hydrometer. Measure the electrolyte gravity of all the cells and verify that it is 1.25 or more.
• If any of the values for the battery voltage, voltage for PCM control, and voltage for DC-DC converter control is low when the engine is started, P0A8D:00 is stored.
• When the engine is restarted by the i-stop control, verify that the following voltages do not decrease lower than 11.5V.
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― Rain sensor (auto-light sensor) power supply terminal
― Audio unit power supply terminal
• If a DC-DC converter control signal is under the following conditions, P0A94:00 is stored.
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― Internal malfunction signal is received.
― Input signal limits the pressure increase time.
― Does not implement pressure increase after a pressure increase command.
• Inspect for an open or short circuit in the following wiring harnesses.
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― DC-DC converter and rain sensor/auto-light sensor
― DC-DC converter and audio unit
Common Inquiry
• With a high capacity audio system or added electronic device connected to the DC-DC converter, engine stop by the i-stop control is inhibited more quickly than normal due to repeated i-stop operation.
• In case after-market electrical devices are installed, the voltage decrease during engine restarting may cause devices to be reset by the direct connection to the +B line without going through a DC-DC converter.
• When electrical devices are added and a direct connection to the battery negative terminal is made without passing the current sensor, a correct electric current amount output from the battery cannot be detected and the PCM incorrectly determines the battery charge condition. As a result, engine restarting failure or battery depletion could occur.
Other
• A DC-DC converter has been adopted to prevent electrical devices such as the audio/navigation system from being reset by the battery voltage (+B line) decrease during engine restarting.
• The PCM detects the battery condition based on the battery output current, or influx electric current amount, measured by the current sensor, and performs i-stop operation permission and generator charging control.