Hope you are the ABS man from when I first logged on. I'm a dealer and sold this car about a month ago. The problem just started this week. I had to drive the car for about 25 mile before the symptoms occurred. I feels like the brakes are holding the car back. It will do this then go away, only to return again.
Answer: I did a search and come up with no bulletins or campaigns for this condition or codes. That said, the high system voltage code is usually caused by actual high system voltage I.E.- alternator problem.
Have had a few internal ABS control modules (EBCM) faulty where it thinks the system voltage is high.
This brings me to the U1300- class II data line short to ground. Sounds like these things are related. A communication problem is either an internal fault in the EBCM, or a harness to the module is shorted somewhere.
I would suggest following the main ABS harness from the module to check for grounded or rubbed through wire(s).
Also, a scanner that can read ABS data is needed to look at what the module sees as system voltage when the problem occurs, and compare that to actual system voltage with a volt meter. I am thinking this is an EBCM problem.
Anti Lock Brakes
Anti-lock brakes are designed to prevent skidding and help drivers maintain steering control during an emergency stopping situation. In cars equipped with conventional brakes, the driver pumps the brakes, whereas in cars equipped with four-wheel ABS, the driver keeps a firm foot on the brake allowing the system to rapidly and automatically pump the brakes. Because the wheels don't lock up, drivers have the ability to steer around hazards if they are unable to stop in time.
When the braking force created by the driver is greater than the tire can handle, the wheel can lock up. Locking wheels can create vehicle instability problems and prevent steering around obstacles in the road. Stopping distance on many slippery surfaces will also increase with locked wheels. Four-wheel ABS prevents wheel lock-up in situations in which the wheels might normally lock, such as on slippery roads.
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