U0177 code meaning
Lost Communication With Restraints System Sensor H
What U0177 means
U0177 is stored when crash sensor H, the eighth remote sensor of the restraint system in J2012 lettering, stops reporting to the airbag control unit. Remote acceleration or pressure sensors detect front, side or rear impacts early and feed the central unit that decides on deployment. No manufacturer documents U0177 publicly. Chrysler's Jeep airbag list from 2006-2010 shows how the block is used, assigning U0170 to U0176 to front and side satellites, but ends before H; so U0177 only appears on vehicles with very many satellites. Siblings U0170 to U0176, U0178 and U0179 name the other sensor positions. Result: airbag warning lamp on, possibly reduced protection in one zone, no MIL. Leave airbag work to a workshop.
U0177 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0177
- Airbag warning lamp on
- Impact detection in the zone of sensor H unavailable
- Code returns immediately after clearing
Common causes of U0177
- Most likelyConnector at sensor H loose, wet or corroded
- PossibleSensor wiring damaged by trim or body work
- PossibleCrash sensor H failed
- Less likelyAirbag control unit input faulty or wrong configuration
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Restraints sensor hCrash signal wiring
What each part of U0177 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 77 | The exact fault in that area. |
What to do next
- Note U0177 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 U0177
What does U0177 mean?
U0177 means "Lost Communication With Restraints System Sensor H". U0177 is stored when crash sensor H, the eighth remote sensor of the restraint system in J2012 lettering, stops reporting to the airbag control unit. It is a generic code, so it means the same on every make.
Is it safe to drive with U0177?
U0177 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0177 fail an emissions test?
U0177 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 U0177 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will U0177 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.