Electrical - Low Battery Diagnosis Tips/TAC Instructions
27 Low Battery Charge: Diagnosis Tips and TAC Instructions
27 12 12
2025360/2
February 28, 2012.
Supersedes Technical DIAGNOSIS AND REPAIR Group 27 number 11 - 09 dated August 8, 2011 for reasons listed below.
Affected Vehicles
Condition
The customer may report a discharged battery when trying to start the vehicle. Condition results in a no start.
Only applies to vehicles with Battery Energy Manager (J644) or Battery Diagnostic Manager (J367)
Technical Background
Not applicable.
Production Solution
Not applicable.
Service
Service
This TSB will provide basic diagnosis steps for discharged batteries, general tips when working with batteries, as well as system verification steps to
ensure the vehicle is configured correctly.
For additional information on known current draw issues, please reference TSBs:
^ 2014127, 27 Battery dead or low after returning to the vehicle. (2007 A6, A8, Q7)
^ 2019143, 27 Battery discharged on some vehicles with Advanced Key (2005 - 2008 A6, Q7)
1. Connect a battery maintainer to the vehicle.
2. Access the battery inside of the vehicle and record serial number of the battery.
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3. For Audi Q7 vehicles with sunroof, inspect the amplifier to verify that there are no water stains on the component. For A4 Avant and A6 Avant
vehicles, operate the rear washer and then inspect the amplifier for washer fluid stains. If no water damage is seen, record pictures of the top and
bottom of the amplifier, as well as the electrical connector in case an Audi Technical Assistance Center (TAC) ticket is required.
4. To determine if the dead battery was customer induced, proceed to the next appropriate section by determining if the vehicle is equipped with a
J367 or J644.
^ For vehicles equipped with J367 - Battery Diagnostic Manager, proceed to Section A. This includes 2009+ A6, Audi Q7 vehicles, 2008+ A5,
2009+ A4, 2009+ Audi Q5, 2012+ A7, 2011 + A8 models, and 2011 + TT and R8 vehicles.
^ For vehicles equipped with J644 - Battery Energy Manager, proceed to Section B. This includes 2008 and older A6 and Audi Q7 vehicles, and
2003-2010 A8 models.
Section A: For vehicles equipped with a Battery Diagnostic Manager (J367)
1. Through GFF, select Function / Component Selection >> Body >> 27 - Battery, Starter, Generator, Cruise control >> Electrical Components >>
A - Battery, manufacturer data.
2. Verify the recorded serial number from the battery matches the number displayed on the Scantool. If the value does not match, adapt the correct
value into the vehicle through A-Battery, Adaptation after replacing. After adapting the battery, verify the new manufacturer data was accepted by
rechecking A - Battery, manufacturer data.
Tip:
Some vehicles may not display the complete serial number in the Scantool. If all of the digits shown on the Scantool are contained within the 10 digit
battery serial number, then no action is needed.
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3. Test the battery through A-Battery, testing. When asked if a new battery has been adapted in the last 5 days, select No to run the test.
If prompted, replace the battery and readapt the new serial number using step 2 above. If the state of charge (SOC) is low, charge the battery using
the appropriate TSB:
2023282, 27 Battery testing and charging - vehicles with BDM (J367)
Tip: Some vehicles will not display the state of charge during the battery test. For these vehicles, run A-Battery, state of charge to get this value.
4. Through GFF, select Function / Component Selection >> Body >> 01 - On Board Diagnostic (OBD) capable systems >> 19-Data Bus On Board
Diagnostic Interface I J533 >> J533-Data Bus OBD Interface, functions >> J533 - Reading History Data
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5. First select 6. Data for energy critical vehicle condition to view the state of the vehicle at critical energy.
6. Inspect the values in the critical energy readout, paying close attention to the values highlighted in Figure 6. These values indicate if the ignition
or any exterior lights were left on at the critical energy state of the battery. In addition, the time and date of the critical energy state is also displayed.
Battery history fields are separated by *. The top value is the date and time, while the bottom value is exterior lights status, PRNDL status, terminal
15 on (in hours), and data bus awake (in hours). In Figure 6, the ignition was left on for 3.0 hours, and two of the exterior lights were on when the
battery reached critical state.
7. Record the date and time indicated. If the highlighted values identify any component was left on, continue to step 8. If nothing is identified,
proceed to step 10.
Tip: Figure 6 also shows the data bus was awake during this time, but it was because terminal 15 was on and can be ignored. Data bus awake time
without terminal 15 on could indicate a problem with a module.
Tip: Some BDM vehicles do not show PRNDL status. In this case, terminal 15 status will immediately follow the light status.
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8. Return to the Reading history data menu and select 4. Shut-off stages history. In Figure 7, the information matching the date recorded by the
critical energy reading is highlighted in red. When reading shut-off history, all dates within 24 hours of critical energy are valid. Battery history
fields are separated by *. Starting at the leftmost highlighted value is date and time, shutoff stage, Aux Heater, battery SOC, available charge, current
battery draw, exterior lights status, Aux heater, PRNDL status, terminal 15 on (in hours), and data bus awake (in hours). In this case, the bottom
highlighted readout in red shows battery SOC at 41%, at 5-09-2010 1:59PM, two exterior lights were left on, and terminal 15 was on for 2.2 hours.
9. Investigate the last reading before battery SOC reaches zero. In Figure 7, this is highlighted in green. This example reading shows two exterior
lights on (Parking lights and headlight low beam), and the ignition on for 2.5 hours. This shows a customer induced condition, as both the critical
energy status and the matching shut-off stage shows energy consumers left on by the customer. If both sections of the history do not show a customer
induced condition, proceed to step 10. If a customer induced condition has been identified, proceed to Section C.
10. On equipped vehicles (A5, Audi Q5, 2009+ A4, 2012+ A6, A7, 2011+ A8), determine if any modules kept the CAN Bus awake by viewing the
Keep awake manager. Return to Function/Component Selection and select 19-Read Data Bus Keep-Awake Manager With this option, the keep
awake events will be displayed, with the most recent being displayed first. If no data exists, then no data will be shown. In Figure 8, on 3-14-2010 at
6:03PM, control module 56 kept the CAN bus awake for .41 hours, while control module 77 kept the CAN bus awake for .40 hours. If the date and
time listed matches (within 24 hours) the date and time in the critical energy reading, then in most cases the first listed module is the cause of the
complaint.
11. In this example, 56 is the cause of the draw. If no data exists in these fields, proceed to step 12. If this completes the diagnosis, proceed to
Section C.
12. Determine if a draw currently exists on the vehicle by using an ammeter with an inductive pickup, such as the 5051B, or similar tool, such as a
Fluke Meter, to check battery draw using the steps below:
a. Start vehicle and operate all consumers on vehicle (radio, lights, heated seats, door locks, sunroof, power liftgate, etc.)
b. Shut off vehicle, open left and right front doors, hood, and rear lid. Manually latch all opened items to gain access to fuse boxes.
c. Zero the ammeter and attached the amp clamp to the negative battery cable. Lock the car using the remote and observe the ammeter, which
should spike briefly as the doors are closed. This will confirm the ammeter is operating correctly. The vehicle may also provide a confirmation
beep to confirm all doors are latched, provided the option is enabled in the MMI.
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d. After 2 hours, the ammeter should read under 0.040 (40mA). If the reading is above 40mA, attempt to locate the source of the excessive draw.
Please reference VW TSB: 2016076, Battery, Discharged; Diagnosis for Excessive Static Current Draw Once diagnosis is complete, or if the
diagnosis is inconclusive, proceed to Section C.
Section B: For vehicles equipped with a Battery Energy Manager (J644)
1. Inspect the mounting point for the ground of the 61 module. Verify it is clean and free of corrosion.
2. Through Self Diagnosis, select On Board Diagnostic (OBD) >> 61 - Battery regulation. The battery serial number is listed in the module data as
in Figure 9.
3. Verify the recorded serial number from the battery matches the number displayed on the Scantool. If the value does not match, adapt the correct
value into the vehicle through Function / Component Selection >> Body >> 27 - Battery, Starter, Generator, Cruise control >> Electrical
Components >> A-Battery, coding after replacing. After adapting the battery, verify the new manufacturer data was accepted by rechecking Self
Diagnosis as explained in step 2.
Tip: Some vehicles may not display the complete serial number in the Scantool. If all of the digits shown on the Scantool are contained within the 10
digit battery serial number, then no action is needed.
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4. Test the battery through A-Battery, testing. When asked if a new battery has been adapted in the last 5 days, select No to run the test.
If prompted, replace the battery and readapt the new serial number using step 3 above. If the state of charge (SOC) is low, charge the battery using
the appropriate TSB:
2023330, 27 Battery testing and charging - vehicles with BEM (J644)
Tip: Some vehicles will not display the state of charge during the battery test. For these vehicles, run A-Battery, state of charge to get this value.
5. Through GFF, select Function / Component Selection >> Body >> Electrical Equipment>> 01-On Board Diagnostic Capable Systems >> 61-
Battery Control >> J644-Energy Management Control Module, functions >> J644-Energy Mgt CtrL Mo., read history data
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6. First select 3. Critical energy balance to view the state of the vehicle at critical energy.
7. Inspect the values in the critical energy readout, paying close attention to the values highlighted in Figure 14. These values indicate if the ignition
or any exterior lights were left on at the critical energy state of the battery. In addition, the time and date of the critical energy state is also displayed.
In Figure 14, the ignition was left on for 2.7 hours, but all of the exterior lights were off when the battery reached critical state.
If the highlighted values identify any component was left on, record the date and time indicated, and continue to step 8. If nothing is identified,
proceed to step 10.
Tip: Figure 14 shows the data bus was awake during this time, but it was because terminal 15 was on and can be ignored. Data bus awake time
without terminal 15 on could indicate a problem with a module.
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8. Return to the Reading history data menu and select 4. Shut-off stages history. In Figure 15, the information matching the date recorded by the
critical energy reading is highlighted in red. When reading shut-off history, all dates within 24 hours of critical energy are valid. Battery history
fields are separated by *. Starting at the leftmost highlighted value is battery state of charge, date and time, exterior lights status, and terminal 15 on
(in hours). In this case, the bottom highlighted readout in red shows battery SOC at 31%, on 9-29-2010 11:22:52 AM, two exterior lights were left
on, and terminal 15 was on for 1.5 hours.
9. Investigate the last reading before battery SOC reaches zero. In Figure 15, this is highlighted in green. This example reading shows two exterior
lights on (Parking lights and headlight low beam), and the ignition on for 1.6 hours. This shows a customer induced condition, as both the critical
energy status and the matching shut-off stage shows energy consumers left on by the customer. If both sections of the history do not show a customer
induced condition, proceed to step 10. If a customer induced condition has been identified, proceed to Section C.
10. Determine if a draw currently exists on the vehicle by using an ammeter with an inductive pickup, such as the 5051B, or similar tool such as a
Fluke Meter, to check battery draw using the steps below:
a. Start vehicle and operate all consumers on vehicle (radio, lights, heated seats, door locks, sunroof, power liftgate, etc.)
b. Shut off vehicle, open left and right front doors, hood, and rear lid. Manually latch all opened items to gain access to fuse boxes.
c. Zero the ammeter and attached the amp clamp to the negative battery cable. Lock the car using the remote and observe the ammeter, which
should spike briefly as the doors are closed. This will confirm the ammeter is operating correctly. The vehicle may also provide a confirmation
beep to confirm all doors are latched, provided the option is enabled in the MMI.
d. After 2 hours, the ammeter should read under 0.040 (40mA). If the reading is above 40mA, attempt to locate the source of the excessive draw.
Please reference VW TSB:
2016076, Battery, Discharged; Diagnosis for Excessive Static Current Draw
Once diagnosis is complete, or if the diagnosis is inconclusive, proceed to Section C.
Section C: Additional tasks
1. If it is necessary to contact TAC for additional guidance, please prepare the following information before opening a contact. If TAC assistance is
not necessary, proceed to the next step.
^ How many times is car in for a battery concern?
^ When did the vehicle come in?
^ Was it towed in or jumped?
^ What day did the customer have the concern?
^ Is/was the date/time in cluster correct? If not, what was/is the date/time displayed?
^ When did you start working on the car?
^ What is the battery serial number in the vehicle?
^ Are there any other electrical concerns on the R.O.?
^ Attach a full GFF Log with complete battery history data and Keep Awake readout (For BDM vehicles).
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^ Attach pictures of the amplifier for Audi Q7, A4 Avant, or A6 Avant vehicles if the amplifier shows no obvious signs of water damage.
2. Before returning the vehicle to the customer, test the battery state of charge and verify that it is above 85%. If the SOC is below this value, charge
the battery until at least 85% is achieved.
3. If the low state of charge was due to customer influence, explain the situation to the customer.
Warranty
This TSB is informational only and not applicable to any Audi warranty.
Additional Information
More information on this system can be found in the following resources:
^ SSP: 972703, Audi Vehicle Batteries and Energy Management Systems
The following Technical DIAGNOSIS AND REPAIR(s) may be necessary to complete this procedure:
^ TSB 2023282, 27 Battery testing and charging - vehicles with BDM (J367)
^ TSB 2023330, 27 Battery testing and charging - vehicles with BEM (J644)
^ TSB 2014127, 27 Battery dead or low after returning to the vehicle
^ TSB 2019143, 27 Battery discharged on some vehicles with Advanced Key
^ VW TSB 2016076, Battery, Discharged, Diagnosis for Excessive Static Current Draw
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service
manuals for the latest information.
