Charging System - Excessive Voltage DTC's Present
27 Excessive Voltage DTCs present in multiple control units
27 12 15
2031145/2
October 23, 2012.
Supersedes Technical DIAGNOSIS AND REPAIR Group 27 number 12-14 dated October 12, 2012 for reasons listed below.
Affected Vehicles
Condition
One or more of the following complaints are reported by the customer regarding electrical features and functions in the vehicle:
^ One or more warning lights on in cluster
^ The DIS or other displays in cluster are blank
^ MMI does not function
^ Windows do not function
^ LED indicators in various buttons inside the vehicle do not light up
Technical Background
3
The voltage regulator on the alternator (Figure 1) can sporadically fail causing the electrical system to experience too high of voltage. As a result, the
affected vehicle electronic components go in to high voltage protection and deactivate sensitive displays and indicators to prevent electrical damage.
When an over voltage condition occurs the vehicle electronics and alternator are protected, thus there is no need to replace the entire alternator
assembly.
Production Solution
A new VDA voltage regulator with better control over the alternator voltage was introduced in to series production.
Service
Check for DTC entries for excessive voltage.
1. These DTCs are only set when a control unit sees input voltages higher than 18V for extended periods of time.
^ DTC 00447 (Functions restriction due to excessive voltage - Upper limit exceeded)
^ DTC U140100 (Function restriction due to excessive voltage)
^ DTC P056300 (System Voltage High Voltage)
2. If more than one over voltage DTC is present in multiple vehicle electronic control units then proceed with the repair suggested in this service
bulletin.
3. If only one control unit on the vehicle is displaying an over voltage DTC then this DIAGNOSIS AND REPAIR may not apply.
4. If no DTCs are present in any electronic control unit but the customer complains of lights flickering or going dim/bright intermittently, then
please reference TSB 2021151, 91 Dash insert, air conditioning control panel or inside light flickers for additional information.
Repair for A4/S4, A5/S5, Cabriolet, Audi Q5, Audi Q7, R8, D3 A8, & C6 A6
1. ONLY replace the voltage regulator and NOT the alternator assembly. The original alternator should function normally with the newer style
voltage regulator fitted.
a. Different vehicles, even of the same model range and model year, can have different alternators from different vendors, i.e. Valeo, Bosch,
or Hitachi. You must reference the actual part on the car and cross reference it with ETKA to determine which voltage regulator is
required for the vehicle.
b. Replace the voltage regulator according to the ElsaWeb repair manual instructions. Repair Manual-Electrical System-Electrical Equipment
General Information-27 Battery, Starter, Generator, Cruise Control-Removal and Installation-Voltage Regulator
Repair for D4 A8, A7, & C7 A6
1. ONLY replace the voltage regulator and NOT the alternator assembly. The original alternator should function normally with the newer style
voltage regulator fitted.
a. Different vehicles, even of the same model range and model year, can have different alternators from different vendors, i.e. Valeo, Bosch,
or Hitachi. You must reference the actual part on the car and cross reference it with ETKA to determine which voltage regulator is
required for the vehicle.
b. Replace the voltage regulator according to the ElsaWeb repair manual instructions. Repair Manual-Electrical System-Electrical Equipment
4
General Information-27 Battery, Starter, Generator, Cruise Control-Removal and Installation-Voltage Regulator
2. Use VSD to determine the software level of the 19 - Gateway data bus control unit. The software level must be 0213 or higher. If the software
level is below 0213, then please update the software using the following SVM information.
a. Follow all instructions in the attached TSB 2011732 00 Software Version Management (SVM), operating instructions.
b. Update the Gateway Data Bus On Board Diagnostic Interface (J533) using the SVM action code as listed in the table above if necessary.
c. This SVM code remedies other issues with the vehicle. Please read TSB 2030903, 90 Sporadic malfunctions during MMI 3G+ complaints
because its possible the customer had additional complaints which could have been remedied by this software update.
Warranty
5
Required Parts and Tools
See ETKA
Additional Information
The following Technical DIAGNOSIS AND REPAIR will be necessary to complete this procedure:
^ TSB 2011732, 00 Software Version Management (SVM), operating instructions.
^ TSB 2021151, 91 Dash insert, air conditioning control panel or inside light flickers
^ TSB 2030903, 90 Sporadic malfunctions during MMI 3G+ complaints
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.
Attachment
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TSB 2011732, 00 Software Version Management (SVM), operating instructions.
