B2505 – Passenger airbag on/off warning lamp failure (Hyundai)

B2505 means the passenger airbag ON/OFF indicator lamp has a fault on your 2019 Hyundai Kona. In plain terms, the dash light that tells you whether the passenger airbag is enabled may not work or may show the wrong state. That creates a real safety risk because you cannot trust the passenger airbag status display. According to Hyundai factory diagnostic data, B2505 indicates a “Passenger airbag on/off warning lamp failure.” This is a Hyundai manufacturer-specific body/SRS-related fault description. The exact circuit routing can vary by platform, so confirm the affected lamp path in Hyundai service information before repairs.

B2505 Quick Answer

B2505 on Hyundai points to a failure in the passenger airbag ON/OFF warning lamp circuit or its control. Fix it by verifying the lamp command, power, ground, and circuit integrity with OEM-approved SRS-safe test methods.

What Does B2505 Mean?

Official definition: Passenger airbag on/off warning lamp failure. What the module detected: a problem with the indicator lamp that shows passenger airbag ON or OFF status. What that means in practice: the vehicle may not correctly display whether the passenger airbag is enabled, even if the airbag system still makes its own enable/disable decision.

What the module is actually checking: on Hyundai platforms, the SRS/airbag control system and the cluster or indicator assembly typically exchange a command and a feedback expectation. The controller looks for a plausible electrical result when it commands the lamp ON or OFF. If it sees an open, short, stuck-on/stuck-off behavior, or an implausible feedback state, it sets B2505. Why that matters: the code points to a suspected trouble area in the lamp circuit path, not a confirmed failed airbag module. You must verify power, ground, lamp drive, and connector condition before replacing parts.

Theory of Operation

Under normal operation, the Hyundai SRS system decides whether to enable the passenger airbag based on occupant detection inputs and internal logic. The system then commands the passenger airbag ON/OFF indicator to match that decision. The indicator informs the driver and front passenger of the airbag status.

B2505 sets when the controller cannot control or confirm the indicator lamp operation. An open circuit can prevent illumination. A short to power or ground can force the lamp on or off. Poor terminal tension, corrosion, or a damaged harness can also distort the signal enough to fail the controller’s plausibility checks.

Symptoms

These symptoms usually relate to the passenger airbag ON/OFF indicator accuracy and reliability.

• Warning lamp passenger airbag ON/OFF indicator does not illuminate during prove-out, stays on, or stays off
• Status confusion indicator shows the wrong airbag state for the seating condition
• Intermittent display indicator flickers or changes state over bumps
• SRS warning airbag warning light may illuminate and store an SRS-related DTC set
• Scan tool data SRS live data may show passenger airbag status changing while the lamp does not follow
• Multiple DTCs additional indicator, cluster, or occupant detection related codes may appear with B2505

Common Causes

• Open circuit in the warning lamp control circuit: A broken wire or poor terminal fit prevents the SRS/occupant detection system from driving the passenger airbag ON/OFF lamp correctly.
• Short to ground in the lamp circuit: Chafed insulation can pull the lamp control line low and create an implausible lamp state that the module flags as a failure.
• Short to power in the lamp circuit: A rubbed-through harness or incorrect backfeed can hold the lamp on and stop commanded state changes.
• High resistance at the lamp connector or splice: Corrosion or a loose terminal increases resistance and causes low current flow, so the lamp does not illuminate at the expected brightness or timing.
• Faulty passenger airbag ON/OFF indicator lamp assembly: An internal LED/board failure can keep the lamp from responding even when the module output and wiring test good.
• Connector damage under the center stack or instrument panel: Stress from trim removal or prior accessory work can spread terminals and create intermittent lamp operation.
• Incorrect bulb/LED type installed after interior repair: Non-OEM components can change circuit load and confuse lamp monitoring logic on Hyundai platforms.
• Related Occupant Classification System (OCS) or SRS logic inhibits lamp command: A separate SRS/OCS fault can block normal lamp state control and make the lamp appear “failed” during self-check.

Diagnosis Steps

Use a scan tool with full Hyundai SRS access, a quality DMM, and back-probing tools intended for low-force terminal checks. Follow Hyundai depowering procedures before touching any SRS-related connector. Do not probe SRS circuits with standard test leads. Use OEM-approved adapters when possible. Plan to perform voltage-drop tests under load, not continuity-only checks.

1. Confirm B2505 with an SRS-capable scan tool. Record DTC status (stored/confirmed vs pending), and save freeze frame data if available. For this body/SRS circuit-type fault, focus on battery voltage, ignition state, and any companion SRS/OCS DTCs present when the code set. Freeze frame shows the conditions at set time. A scan tool snapshot helps catch an intermittent during a wiggle test.
2. Check power distribution first. Inspect related fuses for SRS/cluster/indicator power, and verify the fuse seats tightly. Perform a quick visual inspection along the likely circuit path before meter work. Look for trim screws through harnesses, pinched wiring near the center stack, and evidence of prior radio or dash work.
3. Verify module power and ground integrity under load. Keep the SRS system depowered per Hyundai procedure if you need to disconnect any SRS connectors. If service information allows safe access, perform voltage-drop tests on the module grounds with the circuit operating. Target less than 0.1V drop on grounds. Also check the module power feed voltage-drop under load to catch high resistance in fuse links or ignition feeds.
4. Run a full vehicle DTC scan and address related SRS/OCS faults first. A separate occupant classification or restraint fault can change lamp command behavior. Do not assume the lamp failed if the system never commands a valid ON/OFF state. Document all codes and their statuses.
5. Use the scan tool to view relevant SRS/OCS data PIDs. Look for passenger airbag status, OCS classification, and any available “indicator lamp command” or “indicator feedback” parameters. Compare commanded state to actual lamp operation during key-on self-test and when passenger seat occupancy changes. Do not use a road test to “see if it clears.”
6. Inspect the passenger airbag ON/OFF indicator lamp assembly and its connector. Depower the SRS system before working near SRS wiring. Check for bent pins, backed-out terminals, moisture, and aftermarket splices. Verify correct part fitment if the dash or center stack has been serviced. Confirm no LED/bulb substitutions exist.
7. Inspect the harness from the indicator lamp back to the controlling module. Focus on areas that flex or get disturbed during interior work. Perform a low-force terminal drag test where allowed. Look for rubbed-through insulation, sharp bracket contact, and crushed sections near HVAC controls and the instrument panel supports.
8. Perform circuit integrity tests using OEM-approved methods. With the system in the correct state per Hyundai service information, check for opens and shorts between the lamp and the controlling module. Avoid standard continuity checks across SRS circuits unless Hyundai procedures permit it. If the design uses a low-side driver, verify the control line toggles when commanded. If it uses a data-driven cluster command, verify the network command changes and the cluster output follows.
9. Load-test the lamp feed and ground circuits where applicable. A high resistance connection can pass continuity and still fail under load. Use a suitable test load specified by service practice for non-SRS lamp circuits, or use scan tool output controls if supported. Confirm voltage drop stays low while the lamp should illuminate.
10. Confirm the repair. Clear codes only after completing repairs and reassembling connectors correctly. Perform the Hyundai-required SRS self-check and verify the passenger airbag ON/OFF indicator behaves correctly during key-on and seat status changes. Re-scan for DTCs and confirm B2505 does not return immediately at key-on, which would indicate a hard fault monitored continuously.

Professional tip: Treat B2505 as a “suspected trouble area,” not a failed part callout. Prove the lamp command and circuit response match each other. If the scan tool shows a stable commanded ON/OFF change but the lamp stays fixed, the fault sits in the lamp output path. If the commanded state never changes, resolve upstream SRS/OCS logic or related DTCs first.

Possible Fixes

• Repair open/short in the passenger airbag ON/OFF lamp circuit: Restore wiring integrity, then secure the harness to prevent repeat chafe.
• Clean, tighten, or replace damaged terminals at the lamp connector: Correct terminal tension and remove corrosion that causes resistance and intermittent operation.
• Replace the passenger airbag ON/OFF indicator lamp assembly: Replace only after you verify proper power/ground or control output and a failed lamp response.
• Correct improper aftermarket wiring or incorrect lamp type: Remove backfeeds and restore the OEM lamp load characteristics expected by Hyundai monitoring logic.
• Repair power/ground distribution faults feeding the controlling module or indicator circuit: Fix fuse contact issues, loose grounds, or high-resistance splices confirmed by voltage-drop testing.
• Address related SRS/OCS DTCs that inhibit valid lamp control: Restore correct occupant classification inputs so the system can command and verify the ON/OFF indicator states.

Can I Still Drive With B2505?

You can usually drive a 2019 Hyundai Kona with B2505, but you should treat it as a safety-critical fault. This code points to a failure in the passenger airbag ON/OFF warning lamp circuit or its control. That lamp communicates passenger airbag status to occupants. When it fails, you lose a key safety indicator. Do not ignore it or “wait and see.” Avoid DIY work around SRS wiring. Follow Hyundai SRS depowering procedures before any inspection. Use an SRS-capable scan tool to check related SRS faults and lamp commands before you make any repair decisions.

How Serious Is This Code?

B2505 ranges from a usability issue to a safety concern, depending on what else the SRS module sees. If only the warning lamp circuit fails, the airbags may still function. You still lose the correct passenger airbag status indication, which can lead to unsafe seating decisions. If the SRS module detects additional faults, it may disable parts of the system and turn the airbag warning on. Treat the SRS system as potentially compromised until proven otherwise. Diagnosis requires SRS-safe test methods and proper training. Do not probe SRS-related connectors with standard test leads.

Common Misdiagnoses

Techs often replace the indicator lamp or an overhead/center display component first, then find the code returns. The SRS module sets B2505 because it does not see the expected electrical response. That can come from high resistance in the harness, a loose connector, corrosion, or a power or ground issue feeding the indicator circuit. Another frequent miss involves skipping a full SRS scan and focusing only on the body code. Always confirm the lamp command state in SRS data, verify power and ground integrity under load, and inspect connector pin fit before you condemn any lamp, cluster, or module.

Most Likely Fix

The most frequently confirmed repair direction involves correcting a wiring or connector fault in the passenger airbag ON/OFF warning lamp circuit, not replacing an SRS module. Start with a careful connector inspection at the indicator assembly and any inline connectors in that branch. Fix poor pin tension, fretting, or corrosion and verify proper power and ground feeds. If the scan tool shows the module commands the lamp but the lamp does not respond, the circuit needs continuity and load testing using OEM-approved methods. Confirm the repair by rerunning SRS self-checks and verifying the lamp operates correctly during key-on checks.

Repair Costs

SRS/airbag repair costs vary significantly by component. Diagnosis must be performed by a qualified technician with SRS-capable equipment. Do not attempt airbag system repairs without proper training and safety procedures.

Last updated: March 30, 2026