VIDEO

Informace

Buick

Buick U1255

See the basic definition of a diagnostic error. This will help you to clarify the main causes of the fault code. You will understand the program of the control unit
Basic DTC analysis according to OBD2 protocol standard.

OBD2 or On-Board Diagnostics displays messages for basic group styles. More comprehensible code composition has been standard since 2000. The DTC code consists of five characters and its composition will be shown in this video

Insight into programming

The basic unit for the operation of any computer is the bit. Logic 0 and 1 are expressed by a single bit. Diagnostics The error code is composed of 16 bits. The first two bits define one of the four basic circuits. The video will show you a comprehensive overview of the composition of the error report

A diagnostically understandable description of the Diagnostic Trouble Code

Buick U1255

Basic error definition

High Voltage Contactor Bypass Contactor Stays Activated (HYBRID MODELS)

Cause of DTC

When the ignition switch is turned OFF and MCM power-supply voltage is a minimum of 10.5 V, IMA motor speed 300 rpm, MPI module voltage is between 90-240 V. The difference of the MPI module voltage before the high voltage contactor opening process and the MPI voltage after the high voltage contactor opening process is 3 V or less after at least 10 seconds. WARNING: The IMA system uses high voltage (144 V), before servicing turn OFF the battery module switch.