Network, generic

U0070 Vehicle Communication Bus E (-) Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0070 points to a (-) line of Vehicle Communication Bus E with a path to ground, CAN-Low wherever Bus E is a high-speed CAN. Traffic survives the short, which onsemi and NXP both confirm, so drivers rarely notice anything; onsemi traced a higher node current, because the upper driver stage now pushes current through the 60-ohm termination into ground. On a fault-tolerant low-speed bus the effect is a mode change instead: NXP's TJA1055 reads a never-ending dominant state, needs 0.3-1.6 ms to confirm it, then disables the CAN-Low output stage and keeps going single-wire via CAN-High, with weaker immunity to interference in that mode. Either way the code often lingers in memory unnoticed. No manufacturer documents U0070 publicly. An ohmmeter between CAN-Low and chassis that reads close to zero confirms it.

Likely causes

(-) wire of Bus E chafed against body ground
Harness pinched during installation of trim or accessories
Faulty transceiver pulling CAN-Low to ground

Symptoms

  • Usually no symptom, code found during a scan
  • Occasional interference with audio or display functions on Bus E

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–800
Time1–5 h

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

Parts involved

bus e wiringcan transceiver

Related codes

U0034U0061U0064U0069U0071

References: onsemi.com, nxp.com, nxp.com.