U0070 code meaning
Vehicle Communication Bus E (-) Low
What U0070 means
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.
U0070 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor1 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0070
- Usually no symptom, code found during a scan
- Occasional interference with audio or display functions on Bus E
Common causes of U0070
- Most likely(-) wire of Bus E chafed against body ground
- PossibleHarness pinched during installation of trim or accessories
- Less likelyFaulty transceiver pulling CAN-Low to ground
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus e wiringCAN transceiver
What each part of U0070 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 70 | The exact fault in that area. |
What to do next
- Note U0070 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0070
What does U0070 mean?
U0070 means "Vehicle Communication Bus E (-) Low". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with U0070?
U0070 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0070 fail an emissions test?
U0070 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0070 to fix?
Difficulty: hard. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will U0070 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.