Network, generic

U009D Vehicle Communication Bus J

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U009D covers Vehicle Communication Bus J in general, the tenth letter, and like I it has only this code and a performance code in the list, so open or shorted lines also end up here. No public bulletin names the network behind J, and no manufacturer documents U009D publicly. CARB's requirement for a separate code when a digital input stops communicating is the regulatory basis. Faults that appear after parking deserve attention. Nissan points out that with the key off and the network asleep both CAN wires read 0 V, so voltages must be measured with the bus awake. NXP notes that a single frame at a 500 kbit/s rate may not be enough to wake its TJA1043 reliably, and asks for two in a row. A module that wakes late can therefore look like a bus fault.

Likely causes

Open or shorted wire on Bus J
Module not waking or waking late
Supply or ground fault at a Bus J module

Symptoms

  • Functions of Bus J modules missing after start
  • Lost-communication codes, sometimes only after parking

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 j wiringbus j nodes

Related codes

U007CU0092U009BU009E

References: law.cornell.edu, static.nhtsa.gov, nxp.com.