Originally Posted by BobbyT

You can read the codes on an OBD I 993 without a code reader.

1. Turn on the ignition, but don't start the engine.
2. Depress the accelerator pedal fully for about 3 seconds.
3. The CEL will illuminate steady, and then begin to flash.
4. Ease off the accelerator pedal, and read the codes.

Each code consists of four digits, such as 1121. Each digit will be a number of flashes followed by a pause. Example: Flash pause flash flash flash flash flash = 1500, which means "no fault found". There may be multiple codes. You should have a single flash then a pause, then a single or a double flash. If the flash is double then the fault is intermittent (loose contact) otherwise the fault is constant. And then the following flashes;

11 Supply voltage
14 Engine temp sensor 2
15 Throttle potentiometer
18 Rpm signal
19 Speed signal <- Speedometer
21 Hot Film Mass Air flow sensor
22 Oxygen Sensor (Signal)
23 Oxygen regulation
24 Oxygen sensor
25 Intake Temperature Sensor
26 Ignition timing change
27 Opening winding of idle stabilizer
28 Closing winding of idle stabilizer
31 Knock sensor 1
32 Knock sensor 2
33 Control unit faulty
34 Hall signal
36 Idle CO potentiometer
41 Control unit faulty
42 Fuel pump relay (DME-relay)
43 Tank ventilation relay
44 Air Pump
45 Check Engine warning lamp
51 Injection valve cylinder 1
52 Injection valve cylinder 6
53 Injection valve cylinder 2
54 Injection valve cylinder 4
55 Injection valve cylinder 3
56 Injection valve cylinder 5
67 Ground and plug connections
69 Ground and plug connections


A MAF failure would look like;

FLASH pause FLASH pause FLASH FLASH pause FLASH

Or, you can buy Tore's excellent OBD interface, download the Scantool software (developed by rennlisters!), and see pretty much everything electronic the car is doing on your laptop:

http://www.bergvillfx.com/products.html

He also makes an excellent HID conversion, and gives a rennlist discount.

Originally Posted by gonzilla

Bonus points for the >12 year old thread resurrection.

Originally Posted by ToreB

That might include Aussies too