The UK quattro Network
The UK's mobile Audi 5-cylinder mechanic - 07833 654800, 24x7
Specialist in turbos, quattros, electrics and non-starts

Audi ur-quattro Voice Synthesizer Issues - 1985 Model Year

All 1985 ur-quattros imported by VAG UK are equipped with an autocheck unit with electronic voice synthesiser. This unit was developed so that some twenty sensors could be monitored without cluttering the dashboard with a plethora of warning lights. It also allowed warnings to be prioritized - brake system defects are more important than washer bottle fluid levels.

On many cars this unit has been disabled, either by ignorant radio installers or deliberately to mask faults so that a car can be sold to an unsuspecting buyer.

The voice synthesiser is a critical safety feature and should always be maintained in working order.

For those with imported cars, the German version is here.

On 1985/6/7 cars (autocheck unit 857 907 399E) only one loudspeaker (usually the front left) is taken through the autocheck unit. Pin 16 is connected to the radio NF terminal (ISO connector A pin 2) and grounded to mute the radio/tape/CD and silence the other loudspeakers while the audible warning is issued on the one connected to the autocheck unit.

Voice synthesizer pin assignments from Diagram 19 - 1985 Model Year:

Viewing the connector with the prongs on the right and the side locating lugs at the top, the upper left pin is Pin 1, with numbering proceeding along the connector to Pin 18 at the top right. The bottom row is also numbered from left to right, from 19 to 35. If in doubt, check the wire colours.

Notes

1. The loom includes two three-pin connectors - T3a and T3b. T3a has a single dark blue/green wire looped into all three pins. These connectors should only be pushed together in vehicles that do not have the voice synthesiser. Their purpose is to connect F9 (hand brake warning), F21 (hydraulic pressure warning), F34 (brake fluid level) and F79 (hydraulic pressure warning) to the (single) dashboard light. When they are connected, T3a effectively shorts the voice synthesizer inputs, destroys its discrimination between the signals, and can cause spurious and persistent audible warnings such as "Attention - Brake system defective!" to be issued. If found connected, these connectors should be separated and taped over to prevent inadvertent reassembly.
   There is a simple check to see if T3a/T3b have been improperly connected:
   • Switch off the ignition.
   • Lift the handbrake boot.
   • Pull the grey/yellow wire off the handbrake switch F9.
   • Pull the grey/brown wire off the brake fluid level switch F34.
   • Check for continuity between the two wires.
2. If there is continuity, the centre console must be removed and the black/mauve three-pin connectors separated.
3. The diode pack J67 is shown on the diagram, but is much better explained by Diagram 20. Its function is to combine the handbrake warning and brake fluid level warning into one warning light while retaining separate input for the voice synthesiser. It is physically located on the loom itself, taped to the harness just below the fusebox.
4. The factory diagram has the radio and cigarette lighter connections interchanged. Audi has issued a correction (Berichtigung 000.5755.53.00) which is incorporated above and was added to the wiring diagram page before it was scanned in.
5. The factory diagram omits the feed to Pin 30 - power.
6. Diagram 36 was consulted for the radio connections.

Copyright © The UK quattro Network 2001-2007. All rights reserved.

Kerbside Motors Home Page and Contact Information