Service
Tip:^ During any repair, an approved VW battery charger should be connected to the On-Board battery to prevent battery discharge, which will eventually result in Intervention Load Management and/or low battery voltage with the conditions described in this bulletin.
^ DO NOT attempt to diagnose any DTCs or customer concerns without first connecting the 5051/5052 and checking for DTC in Address Word 09- Vehicle Electrical System Control Module -J519-.
Vehicle Electrical System Control Module
1 Fault(s) detected
00907 000
Intervention load management
If Intervention Load Management DTC is not present:
^ DO NOT complete this bulletin, further diagnosis is required.
If Intervention Load Management DTC is present:
^ DO NOT attempt to diagnose any other DTC or customer concern until you complete the following steps:
Tip:
Failure to provide Diagnosis Log with warranty claim may result in a denied claim.
A. Print out a Diagnostic Log of All DTC's set in each control modules memory using the 5051/5052 (this can be achieved by selecting Vehicle Self Diagnosis, select Collection Services, select Check DTC Memory-Complete, and print the results).
B. First check On-Board battery state of health using Midtronics InCharge 940. See Technical Bulletin Group 27 number 04-01.
C. Once battery condition has been remedied, clear all DTCs.
D. Once the DTCs have been cleared, verify Intervention Load Management DTC IS NOT reset by Central Electronics Module.
If Intervention Load Management DTC was not set again:
- Go to step E.
If Intervention Load Management DTC was set again:
- Further diagnosis is necessary, Go to step G. If DTCs other than Intervention Load Management DTC were set:
- Further diagnosis is required, Go to step H.
Tip:
It is necessary to reset readiness codes if a DTC was present in the ECM and has been erased. Otherwise 5051/5052 will inform you that readiness codes do not need to be set.
E. Using 5051/5052 GFF, set readiness code if required. See "TIP" above, then go to step F.
F. If Intervention Load Management has not returned, attempt to verify customer's concern (if applicable). If customer's concern cannot be verified, cause was most likely due to load intervention and/or low battery voltage.
G. If Intervention Load Management DTC has returned, further diagnosis will be necessary to determine root cause. DO NOT address any other DTCs or customer concern until the issue is remedied. It will be necessary to verify the charging system is functioning properly and that the battery has a good state of health.
H. If a DTC other than Intervention Load Management was set, or customer concern can be verified, the issue will need further diagnosis.
Before beginning diagnosis:
- Print out a Diagnostic Log of all DTCs set in each control module's memory using VAS 5051/5052. This can be achieved as outlined in Item A on a previously shown.
Tip:
Failure to provide Diagnosis Log with warranty claim may result in a denied claim.
During any repair, an approved VW battery charger should be connected to the On-Board battery to prevent battery discharge, which will eventually result in Intervention Load Management and/or low battery voltage with the conditions described in this bulletin.
DF (Dyno Field) and DFM (Dyno Field Monitor) Explanation
The DF or DFM (as found on most VW alternators) is a signal which tells the Engine ECM the amount of load on the alternator.
- This signal is generated by the alternator and can be viewed using an oscilloscope, not a DVOM (see figure as an example of the waveform). The DF/DFM terminal can be found on most alternators used in VW vehicles. However, the DF/DFM terminal may not always be utilized in the specific model.
To determine if the DF/DFM is utilized, a wire will be present in the terminal on the back of the alternator leading to the Engine ECM (this can be verified via wiring diagrams in VESIS).
The Engine ECM transmits the alternator load information via CAN bus to the Vehicle Electrical System Control Module -J519-.
The Vehicle Electrical System Control Module uses the information to determine if more power output is needed from the alternator based on battery voltage. In the event that more power is needed, the -J519- sends a CAN message to the ECM to increase engine speed (i.e., more output from the alternator).
Refer to the flowcharts at the end of this service procedure for an operation overview of the (Intervention Load Management) Function.
For Phaeton W12 engine, the DF signal is utilized by the -J519- Module for the use of Intervention Load Management.
For Phaeton V8 engine, the DF signal IS NOT utilized and thus the -J519- Module uses the Auxiliary (OnBoard) battery voltage in the decision making of Intervention Load Management.
The following Measuring Value Blocks can be viewed using the 5051/5052 which will aid in determining if Load Intervention has been activated:
Address Word 01 (Engine Electronics)
MVB 53 Field 1: Engine RPM actual
Field 2: Engine RPM desired
Field 3: Battery Voltage as seen by the Engine ECM
Field 4: Generator power in % (0 to 100) - this is the DF value, but for VB engine, the value will always be 0 since the DF signal is not utilized.
Address Word 09 (Electronic Central Electrics Module - -J519-)
MVB7
Field 3: Auxiliary (On-Board) Battery Voltage
Field 4: Starter Battery Voltage
MVB 13
Field 1: Intervention Load Management (active or inactive)
Tip:
The flow charts shown are an Operation Overview of the Phaeton Power Management System.
Numbers 1 through 6 in Load Intervention Operation Overview are not to be associated or referenced with numbers 1 through 6 from the previous flow chart.
Use this Overview to familiarize yourself with the Intervention Load Management process.
Once familiarized, you will see that in many cases, systems have been shut down and DTCs may be stored as a result of load intervention to conserve battery voltage (not due to inoperative parts) and that parts replacement is not required.