U0285 code meaning
Lost Communication With Active Grille Air Shutter Module B
Network system Generic code U02xx codes Check engine light
What U0285 means
Module B is the second shutter unit, typically the one behind the lower bumper opening. GM's 2018 ECM tables treat it as LIN device 1 (shutter 2): the ECM sets U0285 after 3 missed counts once the check has been enabled for 400 ms in Run at 11 V or more, Type B with MIL after two trips. Ford monitors it together with A in its OBD summary (signal missing over 10 s). Being low at the front, B collects water and road salt: Stellantis case S2523000095 for the 2025–2026 Ram 1500 reports a lit MIL with U0285 and P05AE and checks the lower shutter harness for corrosion first, and Hyundai's campaign 26-01-026H for the 2026 Palisade replaces corroded lower flap wiring, actuators or sensors. The lower shutters then stay put.
U0285 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of U0285
- Malfunction indicator lamp on, often with P05AE
- Lower grille shutters do not move
- Active air flap warning message
Common causes of U0285
- Most likelyCorrosion in the lower shutter harness or connector from water and salt
- PossibleLower shutter or its wiring damaged by impact or debris
- Less likelyShutter actuator B internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Active grille shutter module bVehicle bus wiring
What each part of U0285 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 85 | The exact fault in that area. |
What to do next
- Note U0285 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 U0285
What does U0285 mean?
U0285 means "Lost Communication With Active Grille Air Shutter Module B". Module B is the second shutter unit, typically the one behind the lower bumper opening. It is a generic code, so it means the same on every make.
Is it safe to drive with U0285?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0285 fail an emissions test?
Yes, it can. U0285 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0285 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U0285 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.