I am trying to diagnosis which sensor in the ABS system has gone/is going bad. The car is a 1988 325iX with a manual transmission. The symptoms are as follows:
1. Turn key to on, ABS light lights up.
2. Start car. Light turns off and all appears well.
3. The first or second application of the brake pedal, even if the car is still stationary, will set off the ABS system and pedal pulses. If I take my foot off the brake pedal it will quit and the ABS light turns on. If I leave my foot on the pedal, the pump will activate indefinitely.
4. Sometimes the symptoms above do not occur and the light simply turns on after ~1-2 miles of driving.
Based on my reading this sounds like a bad sensor. I pulled each wheel sensor and my front driver's side looks rustier and somewhat twisted. All sensors have a resistance between 960 - 1000 ohms. The accelerometer sensor under the hood looks fine but I do not know how to check it. There is 0 ohms of resistance between the terminals. I have not been able to find a new (or guaranteed working) accelerometer so I am hoping it is the wheel sensor.
Any thoughts or insight in to fixing this issue is appreciated. The AWD works great so I would love to have the whole iX package working for the slick roads around here.
Thanks,
Brian
1. Turn key to on, ABS light lights up.
2. Start car. Light turns off and all appears well.
3. The first or second application of the brake pedal, even if the car is still stationary, will set off the ABS system and pedal pulses. If I take my foot off the brake pedal it will quit and the ABS light turns on. If I leave my foot on the pedal, the pump will activate indefinitely.
4. Sometimes the symptoms above do not occur and the light simply turns on after ~1-2 miles of driving.
Based on my reading this sounds like a bad sensor. I pulled each wheel sensor and my front driver's side looks rustier and somewhat twisted. All sensors have a resistance between 960 - 1000 ohms. The accelerometer sensor under the hood looks fine but I do not know how to check it. There is 0 ohms of resistance between the terminals. I have not been able to find a new (or guaranteed working) accelerometer so I am hoping it is the wheel sensor.
Any thoughts or insight in to fixing this issue is appreciated. The AWD works great so I would love to have the whole iX package working for the slick roads around here.
Thanks,
Brian
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