Tracy D Cooper

I recently had my battery and alternator changed..the battery was not a genuine one it seems so I changed it to a genuine one yesterday and it was coded in but this problem is still happening... whilst I am driving along all of a dddem the radio and everything on the inside including the speedo needles at to establish keep cutting out ..I have put it through diagnostics and it is showng exceeds voltage output messages consistently. Has anyone else experienced this please could it be the alternator it something else???

sethroid

I found TSB 271215 - "Charging System - Excessive Voltage DTC's Present," which indicates faulty voltage regulator.

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

The voltage regulator on the alternator 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 service bulletin 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