This is not guaranteed to work, but it did for my car.
Many of us have been plagued with ABS lights on the instrument cluster. Way too many of us in fact. When the car is scanned for codes, the following code is often found:
01276 - ABS Hydraulic Pump (V64)
16-10 - Signal Outside Specifications - Intermittent
There are many threads on Vortex about this code. If you read through all of them. you'll find that most indicate that the ABS control module needed to be replaced. This replacement eliminates the ABS light and code.
I've had this code on and off for a couple of years now and recently, it got to the point where it was coming on EVERY time I drove the car. I did a lot of research on ABS control modules, how they historically fail (there is a large batch of them that fail because of weak electrical leads on an interior circuit board - the fix described below will not correct this problem) and what might lead to an out-of-spec signal. What I found is that the ABS control module is very sensitive to the voltage supplied to it. If the voltage at the module is too low, the module will detect this, assume that something is wrong, log the code and disable to ABS system to protect it from any damage. Obviously, if the voltage to the module is this critical, it is imperative that all electrical connections are good. Since my car is nearly 10 years old now, and the electrical connections for the ABS pump have never been touched, I immediately wondered if my connections were still good enough to keep the voltage to the module high enough. This led me to try the following simple fix - break the original connections and remake them. Hopefully this would reverse any degradation that may have taken place over the 10 years.
On a MKIV, there are three green 30A fuses on top of the battery. The two rightmost ones (S178 and S179) are for the ABS system. On the module itself, there is a large wiring harness that connects the module to power and to the ECU. There is also a smaller harness with two large gauge wires that pass power through the module to the ABS pump.
To fix my problem and eliminate the ABS light and out-of-spec signal, all I did was remove the two ABS fuses and reinstall them a couple of times so that contact surfaces were fresh. Next, I removed the two wiring harnesses from the ABS module and reconnected them (once). The car has been driven a couple of dozen times since this was done for a total of about 400 miles, and the light has not come back on yet. I'm continuing to monitor it, but at this point, it looks like the connections break and remake has elimiated the out-of-spec signal.
I'd be willing to bet that on cars where replacement of the ABS control module eliminated the 01276 code and ABS light, not all of the control modules actually needed to be replaced. Sure replacement worked, but that may solely be due to the fact that the wiring connections had to be broken to replace the module. Some of the modules do have actual internal defects that require replacement, but I'm not convinced that all do. In these cases, replacement of the module is unnecessary and incurs a needless expenditure of $$$.
I'd give this a try if you have the same code. It's free and relatively easy and might just work.
UPDATE - 11-17-08
The ABS light started coming on two weeks ago, approximately 2.5 months after doing the fix. This time I only reseated the two 30A ABS fuses on top of the battery and the ABS light hasn't come back on yet. I would try reseating the fuses first and see if that works. If not, then reseat the connectors on the ABS pump/control module.
Modified by VgRt6 at 10:20 PM 1-5-2009