Check Control Troubleshooting

# Troubleshooting Check Control Unit

#### Oil, Coolant or Washer fluid light

#### Use same procedure for any of the three warning lights

Fluid level OK ? | ~» | No | ~» | Add fluid
Yes
Check fluid level sensor, 0 Ohm when fluid full. OK ? | ~» | No | ~» | Repair ground wire or replace sender
Yes
Plug at sender OK ? | ~» | No | ~» | Repair or replace transmitter
Yes
Wires from senders to check control OK ? | ~» | No | ~» | Repair or replace wires
Yes
Check plug at check control, OK ? | ~» | No | ~» | Repair connector
Yes
Replace check control unit

#### Brake light warning

|  |  |  | All brake lights operating ? | ~» | No | ~» | Check and replace bulbs |  |  |  |
|  |  |  | Yes |  | Bulbs are OK
Supply voltage | «~ | No | «~ | Voltage OK in pin 24 of check control ? |  | Power supply to fuse 12 OK ? | ~» | No | ~» | Supply voltage
|  |  |  | Yes |  | Yes
Check wires, supply voltage | «~ | No | «~ | Voltage OK in pin 25 OK when pedal depressed ? |  | Replace 8 amp fuse
|  |  |  | Yes |  | Replaced but still not lights, or fuse blows
Repair ground | «~ | No | «~ | Ground on bulb tester OK ? |  | Wire from fuse to stop light switch OK ? | ~» | No | ~» | Supply voltage
|  |  |  | Yes |  | Yes
Replace bulb tester | «~ | No | «~ | 4.7 Ohms in bulb tester from ground to green / black wire terminal OK with brake pedal operated ? |  | Check adjustment and condition of brake light switch | ~» | No | ~» | Adjust or replace brake light switch
|  |  |  | Yes |  | Yes
Check or replace wires | «~ | No | «~ | Wire from bulb tester to check control pin 24 OK ? |  | Voltage getting to bulb tester Green / Red wire | ~» | No | ~» | Check wires
|  |  |  | Yes |  | Yes
| «~ | No | «~ | Connector at check control OK ? |  | Voltage present at Green / Yellow and Green / White wires at bulb tester ? | ~» | No | ~» | Replace bulb tester
|  |  |  | Yes |  | Yes
|  |  |  | Replace check control unit |  | Wires from bulb tester to brake lights OK ? | ~» | No | ~» | Repair or replace wires
|  |  |  |  |  | Yes
|  |  |  |  |  | Ground wires to brake lights OK ? | ~» | No | ~» | Repair ground

E30 M3 Repair Manual V2.7. Copyright ©1999-2001 Koala Motorsport & Brett Anderson