Back Index Up Next

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 No
| |
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 Yes
| |
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
 

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