Network, generic

U0089 Vehicle Communication Bus G

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modePossible

U0089 covers Vehicle Communication Bus G as a whole, the seventh of the network letters that SAE leaves for manufacturers to assign. No manufacturer documents U0089 publicly, and neither a service bulletin nor an OBD table names a network for the letter G, so the bus behind it can only be identified from the service information for the specific car. Such umbrella codes rest on CARB's demand that a digital input which stops communicating be recognised and given its own fault code. The code says only that the module has a problem with Bus G as a whole; the neighbouring codes narrow it down: U008A for unreliable traffic, U008B to U0091 for single-wire faults, U0079 for a module that switched itself off the bus. What the driver notices depends on which systems share Bus G.

Likely causes

Damaged wiring or connector on Bus G

Supply or ground fault of a module on Bus G

Internal fault of a module disturbing the bus

Symptoms

Functions handled by Bus G modules fail or act erratically
Several modules hold communication codes

Repair estimate

DifficultyHardWorkshop job

Parts and labour€50–900

Time0.5–5 h

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

Parts involved

bus g wiringbus g nodes

Related codes

U0079 U0080 U008A U0092 U0100

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