so you were right!

clumsily cut and paste from Phil Paynes website; The UK quattro Network


Audi KG turbo engine MAC05 error codes

(You need these working)
Check idle and full throttle switches on throttle body working
Check brake lights working

(This will get the vehicle to a state where any potential faults can generate a code)
Test drive vehicle, attempting to recreate problem condition - minimum 10 minutes, above 80°C, 3,000 rpm and 1.2 bar if possible; accelerate hard in 3rd gear
Leave engine running
If engine will not start, turn on starter for five seconds and leave ignition on
Reading codes erases them - to repeat, repeat test drive

(This bit is how you set the car to output the fault codes)
Remove throttle switch cover or attach remote WOT switch lead
Close full throttle switch by hand or remote WOT switch for ten seconds
Tachometer should read 7000 - "check engine" light on.
Press brake pedal to step through codes:

(This is what those codes look like when displayed, and what they mean)
Tachometer/Check Engine Light/Cause
1000 rpm Off RPM sensor
1000 rpm On Knock control
2000 rpm Off Ignition timing sensor
2000 rpm On Knock Sensor
3000 rpm Off Hall sensor
3000 rpm On Intake air temp.
4000 rpm or
6000 rpm Off ECU vacuum hose or
Idle switch
4000 rpm On Coolant temp. sensor
5000 rpm Off ECU Pressure sensor
7000 rpm Off End of sequence


So that brings us to this question- what problems were you experiencing that would lead a garage to check fault codes?

full info here...

Car won't start intermittently ['87 200 Quattro Turbo]
http://www.classic-audi.co.uk/forum/...ad.php?t=32567