1998 Buick Regal ABS Code C1237

ABS and Check Engine light is on. Computer codes C1237 H.S.V. U1300. CD Player removed by my customer.

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.

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.

buick regal

Download Our Ebook

Fuel Economy, Hybrids & Electric, Recalls And More.

Q and A Main

Main question and answer page. Browse visitor submitted questions and answers from our technicians.

How Things Work

Learn how automotive systems work. From the basics to the latest hi-tech. ABS, Airbags, ignition, fuel injection, emissions and more.

Automotive Basics

A list of basic auto repair checks And maintenance procedures. Pictures, videos, information and more.


Automotive electrcial testing. Learn how to use test lights and multimeters. Learn about basic electrcial theory, sorts, amps, frequecy, fuses and circuit breakers.