BMW Diagnostic Trouble Codes.
All 1989-94 BMW vehicles are equipped with a self diagnostic system for the detection of injection faults. When a fault is detected by the system the Electronic Control Unit (ECU) records the code corresponding to the defect in the ECU\s memory until either:

1. The vehicle battery or the ECU is disconnected.
2. The engine is started 60 times with no recurrence of the fault.
3. The ECU memory is cleared using the Bosch KTS300, CARSOFT BMW software or the CS1000 BMW hand scanner.

To review the FAULT CODES from the ECU memory use the following procedure:

1. Turn the ignition switch to the \engine run\ position.
2. Depress the gas pedal to the floor 5 times.

The CHECK ENGINE light will blink out the FAULT CODES starting with the lowest number first. These FAULT CODES consist of 4 digits each separated by a short pause (ie. blink pause blink blink pause blink pause blink translates as 1 2 1 1).