U008E Vehicle Communication Bus G (-) Open
With U008E the (-) wire of Vehicle Communication Bus G is open, CAN-Low where Bus G is a CAN. U008E is not documented publicly by any maker. Seen with an oscilloscope, CAN-Low beyond the break no longer drops from about 2.5 V to the 1.5 V that Texas Instruments gives for a dominant bit, so receivers there get only the CAN-High half of the signal and less margin against noise. Termination suffers as well: TI recommends that the 120-ohm resistors sit at the line ends and not in a node, because a disconnected node takes its terminator with it, and a broken CAN-Low can cut one of them off in the same way. Transceivers do not flag the open line themselves, as NXP points out. Checking resistance between the wires from both sides of the vehicle helps locate the gap.
Likely causes
Symptoms
- Modules beyond the break respond only sometimes
- Code comes and goes with temperature or road shocks
Repair estimate
Typical range across vehicles; the real cost depends on what the testing finds.