U0478 code meaning
Invalid Data Received From Restraints System Sensor H
What U0478 means
U0478 flags invalid data from restraints sensor H, the counterpart of lost-contact code U0177. No manufacturer publishes which sensor carries the letter H; the Chrysler fault tables filed with NHTSA under PE11-019 stop at G. An H implies at least eight satellites. Bosch's arithmetic allows that: besides acceleration satellites it wires two or four pressure sensors inside the door cavities, so four door sensors plus two side and two front acceleration sensors already add up to eight. Bosch's small AB light unit, with six sensor inputs at most, could not serve such a layout. Airbag lamp on, no MIL.
U0478 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0478
- Airbag warning lamp on
- Code present only in the restraints controller
Common causes of U0478
- PossibleMoisture or a damaged seal affecting a door-mounted pressure sensor
- PossibleSensor line damaged, for example in a door hinge harness
- Less likelyRestraints controller coded for a sensor set that is not fitted
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Restraints system sensor h
What each part of U0478 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 78 | The exact fault in that area. |
What to do next
- Note U0478 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 U0478
What does U0478 mean?
U0478 means "Invalid Data Received From Restraints System Sensor H". U0478 flags invalid data from restraints sensor H, the counterpart of lost-contact code U0177. It is a generic code, so it means the same on every make.
Is it safe to drive with U0478?
U0478 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0478 fail an emissions test?
U0478 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 U0478 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U0478 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.