BMW E32 & E34 On-Board Computer (BC3 & BC4) Documentation: Fault Codes, Pinouts, Real-Time Data and Actuator Tests
Fault Code List and Definitions:
2 Data bus line fault
5 Temperature sensor fault
— Pin 05 of the BC connector to the temperature sensor.
6 Ignition switch terminal 15 fault
— Pin 6 of the BC connector.
7 Vehicle speed signal fault
8 Terminal R (Reverse light signal) fault
— Pin 8 of the BC connector.
12 Fuel level sensor fault
— Condition detected: Fuel tank fill > 30 liters and the reserve contact is active. Fault in the fuel gauge sender (pin 12) or the reserve contact (pin 26).
15 Data bus line to instrument cluster
— Pin 15 of the BC to the instrument cluster, beige connector, pin 3. Ignore this fault if a standard instrument cluster is installed (without the capability for parallel display on the on-board computer).
18 Temperature limit warning gong fault
— Pin 18 of the BC to the warning gong, pin 3.
19 Time limit warning gong fault
— Pin 19 of the BC to the warning gong, pin 2.
20 Auxiliary heater system fault
— Pin 20 of the BC to the auxiliary heater relay control unit.
21 Auxiliary ventilation system fault
— Pin 21 of the BC to the auxiliary ventilation relay control unit.
23 Alarm siren fault
— Pin 23 of the BC to the DWA (anti-theft system), pin 3.
24 Anti-theft system (DWA) fault
— Pin 24 of the BC to the DWA, pin 1 and to the DME (Engine Control Unit), pin 38.
Fault codes correspond to the pin numbers in the connector!
On-Board Computer Connector: X501, 26-pin, green color.
Pin Assignment for the Connector:
1 — Hood/Radio contact
2 — DAC (Digital Analog Converter)
3 — RxD (Receive Data)
4 — Terminal 31 (Ground)
5 — Temperature sensor
6 — Terminal 15 (Ignition switch power)
7 — Speedometer output signal
8 — Terminal R (Reverse light signal)
10 — Terminal 50 (Starter signal)
11 — Anti-theft system (DWA)
12 — Fuel level sensor
13 — Fuel temperature sensor
15 — LAC (Light Automatic Control?)
16 — TxD (Transmit Data)
17 — Terminal 30 (Battery constant power)
18 — Gong T2 (Temperature warning)
19 — Gong T1 (Time warning)
20 — Auxiliary heater system
21 — Auxiliary ventilation system
22 — Terminal 58g (Illumination dimmed)
23 — Alarm siren
24 — Code (Anti-theft code signal)
25 — Steering column stalk switch
26 — Fuel tank reserve contact
Real-Time Data Parameters:
Inputs:
— Terminal R: ****
— Terminal 15: ****
— Terminal 50: ****
— Steering column stalk switch: ****
— Automatic diagnostic system key: ****
— Reserve contact: ****
Outputs:
— Anti-theft system: ****
— Auxiliary heater system: ****
— Auxiliary ventilation system: ****
— Time limit warning LED, left: ****
— Time limit warning LED, right: ****
— Limit value warning LED: ****
Actuator Activation / Component Tests
1 Display and all LEDs
— All segments of the on-board computer display and all LEDs are activated for approximately 10 seconds.
2 Temperature limit warning gong
— The temperature limit warning gong is activated at a frequency of 1 Hz for approximately 3 seconds.
3 Limit value / Code violation warning gong
— The limit value / code violation warning gong is activated at a frequency of 750 Hz for approximately 3 seconds.
4 Time limit warning gong
— The time limit warning gong is activated at a frequency of 1 Hz for approximately 3 seconds.
5 Auxiliary heater system
— The output for the auxiliary heater system is activated for approximately 5 seconds.
Important Note!
— No combustion occurs!
— After the test concludes, the heater fan continues to run for approximately another 2 minutes!
6 Auxiliary ventilation system
— The output for the auxiliary ventilation system is activated for approximately 5 seconds.
7 Anti-theft system (DWA)
— The anti-theft system is activated and remains active until it is deactivated via MoDiC or until a button on the BC4 is pressed.
8 Alarm siren
— The output for the alarm siren is activated for approximately 1 second.