In the past year or so my '03 GT has developed a strange habit: every now and then the 'general warning' light stays on after starting up and pulling away. The ABS flashing light goes out as it's supposed to. The weird part is that I can stop, shut off the bike, and restart and the light goes off the way it's supposed to when I pull away. I can't detect any problems with brake lights or anything else the general warning is supposed to indicate.
This behavior does not happen any more or less frequently that it did when it first started.
I'm thinking I don't have a real issue to worry about. Has anyone else experienced this? If so, what was the problem and the fix?
Thanks in advance for any insights.
On all Integral ABS with servos (mainly 2002-2006 in USA market), there 2 scenarios where you will see a STEADY (non flashing) "General warning" (triangle shaped) alone without any other ABS warning:
- CAUSE CASE 1) The single rear / tail light bulb is either burned, loose , bad contact, OR has been modified using a non std bulb that does not pull the same amperage (like a LED or any of these special rear flashing kit). The bulb is being operated by the ABS modulator electronics and the current to it is monitored.
The monitoring circuitry in the ABS modulator is able to tell if either the brake filament or the night light filament (inside the single bulb) is defective. In both cases it will set the "general warning" steady as a warning something needs to be fixed.
IF the night (low intensity) filament is burned, it will use the brake filament at a lower intensity (making you and the driver behind believe all is well). In such case, the "general warning" goes AND STAYS ON starting from about 1 second after ignition ON. Any low amp draw (like a an alternate LED replacement bulb) will cause the same as a burned bulb as-far-as the monitoring circuit is concerned.
On the other hand, If the higher intensity Brake filament is burned instead, the "general warning" will go on ONLY when you apply either brake Lever/Pedal for the fist time after ignition ON cycle - it will stay on thereafter until ignition is turned OFF (unless bulb contact is intermittent and bulb is in fact good). Of course the remaining low wattage filament cannot emulate a high intensity brake light (so you have no brake light signal visible from rear).
- CAUSE CASE 2) One of the brake switches (pedal/lever) does not make the opening circuit it should do when lever/pedal is activated.
Background info: on these Integral-Abs models, the brake switches have reverse logic compare to most brand (and also compare to older BMW). At rest, these switches have continuity and in pressing the lever/pedal, the circuit is opened (no continuity). With such design, after ignition ON, the ABS modulator can check if both brake switches have continuity (no wire cut or switches disconnected) - the manual explicitly tell you to leave you hands OFF the brake during ignition ON cycle (wait about 5 seconds for the internal ABS self check to finish). If parked on an incline, leave it in 1st gear during the 5 secs self-check , then use the brakes as needed)
Besides the internal self-check of the brake switches, the Integral-ABS system also monitors the pressure cause by lever / pedal application using hydraulic internal pressure sensors located inside the ABS modulator. If pressure is detected (up to a certain threshold) without any previous brake switches signal, it will trigger the "general warning" steady (only when the brake pedal / lever is applied depending on the defective switches).
CONCLUSION: check / inspect / change the bulb for a std 21/5 watts bulb (although just a bit more wattage the 1157 is more common in auto-parts and will not cause any issues)
Pay attention to when the "general warning" shows up the 1st time - immediately after igniton ON ..or.. later when brakes are applied. Apply front and rear separately to isolate problem. WATCH for a non functioning brake light signal visually to confirm a bulb problem (covers 1 case only).
Brake switches: assuming the 1st occurence of "general warning" is always right after Rear Brake application, check carefully as this one is more subject to damage by a low-speed drop AND also debris. The bolt of the pedal may not make proper constant contact with the metal tab. Check this YouTube link for my cruise-control troubleshooting video starting at position 08:28 (min:sec) to better listen and see how it should behave (put your volume up):
FINALLY... If all these facts cannot help you pinpoint the cause, you will need an ABS module fault code readout using dealer's computer OR a GS911.