Code
B285100
HYUNDAI
B — Body
DMB Antenna Open State
Views:
UK: 18
EN: 23
RU: 16
AI status
Completed
Completed
100%
Causes
- Broken or cut coaxial cable between antenna and head unit
- Disconnected or corroded antenna connector
- Failed DMB antenna assembly (mast/element)
- Damaged antenna ground or shielding
- Blown fuse or failed antenna power feed/relay (if applicable)
- Faulty infotainment/head unit input circuitry or connector
Symptoms
- No DMB reception or very weak/no signal for DMB channels
- Infotainment shows DMB antenna error or reduced signal strength
- Antenna mast fails to extend or responds intermittently (if motorized)
- Other radio bands (FM/AM) may be affected if shared antenna or ground is compromised
What to check
- Retrieve and record DTC with diagnostic tool; verify B285100 presence and any related body/comms codes
- Visual inspection of roof antenna assembly, base, and connectors for damage or water ingress
- Inspect wiring harness routing for chafe, pinches, or breaks between antenna and head unit
- Check connector pins for corrosion, bent pins, or loose terminals
- Verify relevant fuse(s) and power/ground circuits for antenna (if powered)
- Perform continuity/resistance check of coax/shield between head unit connector and antenna base
Signal parameters
- Antenna continuity: expected low resistance (near 0–5 ohms) between feed and antenna element; open = OL or infinite ohms
- Shield continuity: continuity between coax shield and chassis ground
- Antenna feed voltage (if powered mast): typically battery voltage when deployed ~11–14 V (varies by model)
- Infotainment signal input: very low/no RF level (dBm) reported for DMB band when open circuit present
- Connector pin voltage/ground presence at head unit: ignition/accessory on vs off
Diagnostic algorithm
- Confirm DTC B285100 with scan tool and note any freeze frame or related codes (U-codes or other B-codes)
- Perform a visual inspection of the antenna and roof area for physical damage or water entry; remove trim as needed
- Inspect and reseat antenna connector at base and at the head unit; clean corrosion with electrical contact cleaner if found
- Check fuse(s) and relays related to antenna/infotainment; replace blown fuse if necessary and retest
- Measure continuity of the coaxial center conductor from the head unit antenna input to the antenna element; replace harness or repair if open
- Check continuity of coax shield to chassis ground; repair shielding if open or intermittent
- With ignition on, measure voltage at the antenna power pin (if applicable); if no power, trace back to fuse/relay/head unit output
- Perform wiggle test on harness while watching for changes in signal or DTC; identify intermittent faults
- If wiring and power are good but antenna element is open, remove and bench-test or replace antenna assembly
- If antenna assembly tests good, test or replace the head unit/infotainment input module or consult manufacturer repair procedures for module-level tests
- Clear codes and perform functional/road test to confirm repair; re-scan for reappearance of B285100
Likely causes
- Broken/disconnected coaxial cable or connector at roof/antenna base
- Corroded or water-damaged antenna connector or wiring
- Failed antenna assembly (open internal element)
- Poor ground or shield continuity
- Head unit/antenna input failure
Fault status
Status
B285100 — DMB antenna open circuit detected. Antenna feed or connector open; DMB reception unavailable.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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