Battery - Minimum Voltage Requirements
Group:00Number: 03-11
Date: Dec. 4, 2003
Subject:
Perfect Delivery Inspection (PDI), Minimum Battery
Voltage Requirement
Model(s):
Phaeton 2004
Condition
If the On-board Power Supply battery voltage signal drops below 12.2 volts for a defined period of time, the On-board Power Supply Management System initiates a Convenience Electrical Equipment shutdown sequence.
The result is that convenience electrical equipment items are switched OFF or are reduced by their control modules based on the importance of each item to proper vehicle operation and comfort.
Items switched off or have power reduction to may include but are not limited to:
^ Luggage compartment remote release (will not function).
^ Sunroof (will not function).
^ Keyless entry (will not function).
^ Wiper Park position.
^ Mirror and steering wheel heaters (switched
OFF).
During this process, some components may also cause Diagnostic Trouble Codes (DTCs)s to be stored in DTC memory.
^ This may give the false impression that components have failed when the simple answer is the battery voltage is too low.
For additional information, see:
^ Self-study program no. 895303, The Phaeton On-board Power Supply Design and Function.
Service
^ Prior to performing the PDI, use the diagnosis tree (shown) to determine if battery needs to be charged (also described in detail as follows).
When working with Batteries, ALWAYS review CAUTIONS and WARNINGS in:
^ Repair Manual Group 27 "Battery General information" and "Battery charging" and "Load test"
^ "Vehicle Batteries" in Owner's Manual, Booklet 3.2. Battery, checking prior to performing the PDI:
- Locate the On-board power supply battery (an Absorbent Glass Mat (AGM) sealed battery) which is located behind the cover in the luggage compartment on the left side.
- Test the battery using the Midtronics MCR340V battery tester see:
- Repair Manual Group 27 "Load test"
- Record battery voltage and 14 digit battery test code.
^ Minimum battery voltage must be at least 12.5 volts!
Even if the Midtronics Tester indicates "Good Battery":
If battery voltage is less than 12.5 volts, it will need to be charged.
Battery, charging
- Connect the INC-940 battery charging station.
- Select the AGM setting.
- Enter the DIN rating.
- Charge the battery in "automatic" mode.
- Record final battery voltage and 14 digit battery lest code.
Battery, maintaining during repairs
- Always, connect battery maintainer CXC 2140 during the PDI and other normal diagnostic checks.
^ This ensures that the power supply voltage remains above 12.2 volts.
Note:
If extensive checks or repairs are required which take longer than 30 mm..
- Connect the INC-940 battery charging station.
- Charge the battery in "Manual" mode.
^ This ensures that the power supply voltage remains above 12.2 volts.
^ Ensure that unless absolutely necessary, the key is removed from the ignition switch. When the key is in the ignition switch communication may be activated between some control modules, thereby increasing power drain on the battery.