Network, generic

U008A Vehicle Communication Bus G Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U008A means Vehicle Communication Bus G still carries traffic, but not cleanly. No manufacturer documents U008A publicly. If Bus G is a CAN, every node counts its own transmit and receive errors; Wikipedia describes that a node turns error passive once a counter exceeds 127 and leaves the bus only after the transmit count passes 255, which is the bus-off case coded as U0079. U008A covers the range below that, with repeated frames, delays and occasional corrupted data. Signal quality is a frequent reason: Texas Instruments recommends unterminated stubs of no more than about 0.3 m on high-speed CAN, because reflections in longer branches, such as from tapped-in accessories, can distort bits at the sampling point. CARB requires communication errors to be detected alongside total loss.

Likely causes

Loose or corroded contact in a Bus G connector
Aftermarket device tapped into Bus G with a long branch
Termination of Bus G missing or out of tolerance

Symptoms

  • Short dropouts of functions on Bus G
  • Messages that appear briefly and vanish

Repair estimate

DifficultyHardWorkshop job
Parts and labour€50–800
Time0.5–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

bus g wiringmodule connector

Related codes

U0079U0081U0089U0093

References: en.wikipedia.org, ti.com, law.cornell.edu.