U0093 code meaning
Vehicle Communication Bus H Performance
What U0093 means
U0093 says Vehicle Communication Bus H works, but with too many errors or too much delay. U0093 appears in no public manufacturer document. Unlike the wire codes U0094 to U009A, nothing is open or shorted; the signals are merely unreliable. A frequent background is a ground offset between modules. Texas Instruments describes the potential difference between the grounds of sender and receiver as common-mode voltage, with ISO 11898 requiring tolerance from -2 to +7 V, and lists erratic resets, lock-ups and corrupted data as results when it is exceeded. In a car this happens with loose or corroded ground points. On a CAN, each corrupted frame triggers an error frame and a repeat, which costs bandwidth long before any node is shut off.
U0093 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0093
- Functions on Bus H drop out briefly and recover
- Modules restart or freeze sporadically
Common causes of U0093
- Most likelyLoose or corroded ground point of a Bus H module
- PossibleLoose terminal causing short interruptions
- Less likelyInterference coupled in from nearby loads or retrofitted devices
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus h wiringModule connector
What each part of U0093 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 93 | The exact fault in that area. |
What to do next
- Note U0093 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 U0093
What does U0093 mean?
U0093 means "Vehicle Communication Bus H Performance". U0093 says Vehicle Communication Bus H works, but with too many errors or too much delay. It is a generic code, so it means the same on every make.
Is it safe to drive with U0093?
U0093 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0093 fail an emissions test?
U0093 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 U0093 to fix?
Difficulty: hard. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will U0093 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.