U0098 code meaning
Vehicle Communication Bus H (-) Low
What U0098 means
U0098 is stored once the Bus H (-) wire, CAN-Low on a CAN, sits too low, normally from a short to ground. No manufacturer has made a use of U0098 public. With fault-tolerant low-speed CAN the short unfolds in stages: the receive pin of NXP's TJA1055 initially stays dominant without pause; once a time-out has passed, the chip disables its CANL driver and goes on receiving single-wire over CANH. Once the short is removed, normal levels return and the chip goes back to differential mode. Communication thus survives, but with less noise margin. A high-speed CAN also keeps running in this state, as onsemi measured, though with distorted levels. A resistance check of that wire against chassis, battery disconnected, confirms it.
U0098 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 U0098
- Usually no noticeable symptom
- Occasional errors on Bus H in electrically noisy conditions
Common causes of U0098
- Most likely(-) wire chafed to ground
- PossibleHarness pinched by a fastener or panel
- Less likelyFaulty transceiver pulling the (-) line to ground
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus h wiringCAN low wire
What each part of U0098 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 98 | The exact fault in that area. |
What to do next
- Note U0098 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 U0098
What does U0098 mean?
U0098 means "Vehicle Communication Bus H (-) Low". U0098 is stored once the Bus H (-) wire, CAN-Low on a CAN, sits too low, normally from a short to ground. It is a generic code, so it means the same on every make.
Is it safe to drive with U0098?
U0098 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0098 fail an emissions test?
U0098 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 U0098 to fix?
Difficulty: hard. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will U0098 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.