Battery Management System Acura ZDX I

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System Description

This system consists of the battery sensor, the gauge control module, the driver's MICU, the passenger's MICU, the alternator, and the PCM.

The battery sensor measures current, voltage, and temperature values of the battery in all ignition switch positions or all power modes. This data is used to control the alternator output, the idle speed, and the interior lights. These are the advantages of this system

1. Helps to prevent over-discharge of the battery
2. Helps to protect engine cranking amps
3. Helps to extend battery life
4. Helps to improve fuel economy
5. Helps to alert the client of battery condition

Battery Management While Ignition Switch in LOCK (0) or the Vehicle Ignition in the OFF mode, and with Electrical Devices ON

When the battery sensor detects the battery voltage decreasing, that information is sent to the gauge control module via the UART line. The gauge control module then operates a beeper, and displays the message Switch Off All Lights and Electrical Devices on the multi-information display (MID) to inform the client that electrical devices should be turned off. If electrical devices are not turned off and the battery voltage decreases more, the gauge control module sends an interior lights off signal to the driver's MICU and the passenger's MICU via the B-CAN line. Based on that signal, the units cut off the ground circuits of the interior lights and turn them off.

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Battery Management While the Engine is Running

While the engine is idling, the battery sensor measures current, voltage, and temperature values of the battery, and this data is sent to the gauge control module via the UART line. The gauge control module sends the idle speed control signal and alternator control signal to the PCM via the F-CAN A line. Then, based on those signals, the PCM determines the idle speed that is appropriate for the current state of charge of the battery/ and also controls the alternator output. Because of these functions, battery condition is maintained, and fuel economy is improved.

If the battery sensor detects any problems, a warning message is shown on the multi-information display (MID) to inform the client that the system needs attention.

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Note. If there are any problems with the charging system or the battery, the charging system indicator comes on at the same time. The most common causes for "Battery Charge Low" messages are: Short-trip driving Using the vehicles electrical devices, like the audio system, or aftermarket electrical devices for long periods of time with the engine OFF and the ignition switch is turned to ON (II), or the vehicle ignition is in the ON mode. If the "Battery Charge Low" warning is displayed after fully charging the battery, disconnect the gray 2-pin connector next to the Battery Sensor for 10 seconds, then reconnect the connector; and the warning is removed from the display. If you need to replace the battery, replace it with a new battery of the same group size.

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Symptom Troubleshooting

MID Indication Possible cause Diagnostic procedure Notes Faulty connector Faulty wire harness Faulty battery sensor Inspect the connector to be sure it is making good contact. Check for an open or high resistance in the wire. Disconnect the battery sensor from the battery negative terminal and reconnect it. Check for DTC. Replace the battery sensor. The battery sensor is initialized and recalibrated automatically after reconnecting. To do this process quickly, turn off all electrical loads, lock all doors with the transmitter, and remove the No. 11 (7.5 A) fuse from the auxiliary under-hood fuse/relay box. Then disconnect the battery sensor 2P connector, wait 5 seconds, reconnect it, and reinstall the fuse. The battery sensor will be initialized and recalibrated within 10 minutes. Faulty battery Test the battery (see BATTERY TEST ). Faulty alternator Low battery voltage Low battery charge Troubleshoot the charging system (see SYMPTOM TROUBLESHOOTING INDEX ). Check for excessive parasitic draw with the ignition switch in LOCK (0) with the key removed, or the vehicle ignition in the OFF mode. Long-term parking, frequent short trips, aftermarket accessories, or using any electrical loads without the engine running for long periods may cause this symptom. *: 10-11 models

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Battery Sensor Input Test

Note. Before testing, make sure the battery ground cable is installed correctly, and make sure there is continuity between the battery negative terminal and ground terminal G1.

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1. Disconnect the 2P connector (A) from the battery sensor (B).
2. Inspect the connector and socket terminals to be sure they are all making good contact. If the terminals are bent, loose, or corroded, repair them as necessary, and recheck the system. If the terminals look OK, go to step 3.
3. With the 2P connector still disconnected, do the following input tests. If any test indicates a problem, find and correct the cause, then recheck the system. If all the input tests prove OK, replace the battery sensor. Cavity Wire Test Condition Test: Desired result Possible cause if desired result is not obtained 2 ORN Under all conditions Measure the voltage to ground: There should be battery voltage. Blown No. 11 (7.5 A) fuse in the auxiliary under-hood fuse/relay box An open or high resistance in the wire 1 WHT Disconnect gauge control module connector A (32P) Check for continuity between terminal No. 1 and gauge control module connector A (32P) terminal No. 12: There should be continuity. An open in the UART wire Check for continuity to ground: There should be no continuity. A short to ground in the UART wire

See also:
• BATTERY TEST
• SYMPTOM TROUBLESHOOTING INDEX