ABS Light on and off

[eddiefisher]

Need some help with my 1990 911 Targa and when driving it sometimes the ABS light comes on and sometimes it does not any advise on where to start looking or what I might need to replace I would say the sensors but just checked the price and wow 228.00 for one that's a expensive reparir to replace all 4. Thanks for any advise.

Eddie

[Dan J]

Believe it or not it's probably your spark plug wires. Disable the ignitions one at a time by unplugging the driver on the coils one at a time and see if it skips if so their you go
More articulate fellows then I have explained this in the 964 section here and on Rennlist
Good Luck

[Bob Kontak]

From my handful of ABS wrestling adventures, I would suggest paying someone with the correct hand held diagnostic tool to isolate the problem. One of those $8,000 Snap-on tools.

$100 maybe?

Not sure how sophisticated the on-board diagnostics were in 1990 regarding storing historical faults. But if the light comes on frequently enough, it would not be a burden for a tech to ride around for a few minutes to trigger the light.

It usually is one of the sensors. There are ways to check the pulses the sensors emits but I recall having to craft a back-pinning apparatus and I still never felt comfortable as the sensor would only emit a partially screwed up signal below 5 MPH. I was not savvy enough to pick that up.

At the shop, the guy confirmed which sensor was weak in the parking lot.

I would not remove any of the sensors from the wheels. I don't know what the 911 ones are like but I know that in the rust belt, bad things can happen to the sensor when you attempt to pull them out.

[Bob Kontak]

Originally Posted by Dan J

Believe it or not it's probably your spark plug wires.

Hell yeah! I would try that in a heartbeat if someone has any knowledge of another angle.