Code
B1488
MITSUBISHI
B — Body
OFF alarm lamp circuit fail
Views:
UK: 10
EN: 13
RU: 12
AI status
Completed
Completed
100%
Causes
- Burned out or failed indicator bulb / LED
- Open circuit (broken wire) between BCM and lamp
- Short to ground or short to battery in lamp circuit
- Corroded or loose connector/terminal at the lamp or module
- Blown fuse protecting the lamp circuit
- Poor ground at lamp or module
Symptoms
- ‘OFF’ alarm indicator does not illuminate when expected
- Indicator remains on continuously or flashes erratically
- Alarm system may not indicate armed/disarmed status correctly
- Related security/immobilizer warnings or unusual behavior
- Diagnostic trouble code B1488 stored
What to check
- Verify customer complaint and reproduce symptom with ignition/lock/unlock events
- Visually inspect indicator lamp assembly and wiring harness for damage or corrosion
- Check fuse(s) for the alarm/indicator circuit
- Inspect and reseat connectors at the lamp and BCM/alarm module
- Scan BCM/alarm module for additional related codes or faults
- Backprobe lamp connector to measure voltage and ground when lamp is commanded
Signal parameters
- Lamp supply voltage: ~12 V when lamp is commanded ON (measure at lamp connector)
- Lamp ground continuity: near 0 ohms to chassis ground
- Open-circuit: infinite resistance between lamp and BCM output
- Short-to-ground: very low resistance between lamp feed and ground with circuit fused removed
- Current draw: small milliamps for LED, higher (hundreds of mA) for incandescent bulbs
Diagnostic algorithm
- Confirm the code and symptoms using a scan tool; record freeze frame and related codes.
- Visually inspect the lamp, socket, and wiring for obvious damage, corrosion, or water intrusion.
- Check and replace fuse(s) for the alarm/indicator circuit if blown; retest.
- Remove lamp/assembly and inspect bulb or LED. Replace nonworking bulb/LED and clear code to test.
- With connector disconnected, measure resistance/continuity between lamp terminal and BCM output/ground. Look for open or high resistance.
- Backprobe the lamp connector while commanding the lamp (via key/BCM function or friend operation) and verify correct supply voltage and ground switching.
- If voltage is present at the BCM output but lamp does not light, verify lamp/connector wiring for short to ground or harness fault. If no voltage, test BCM output pin for short to power/ground or internal BCM fault.
- Wiggle test wiring while monitoring to find intermittent faults. Repair damaged wiring or replace connector as needed.
- After repairs, clear the code and cycle the system several times to confirm the fault does not return. If wiring and lamp check good and code persists, consider replacing or professionally repairing the BCM/alarm module.
Likely causes
- Failed indicator lamp (bulb or LED)
- Connector corrosion or loose connector at lamp
- Open or damaged wiring in lamp harness
- Blown fuse for the alarm/indicator circuit
Fault status
Status
OFF alarm lamp circuit fault detected by body control module — possible open/short/failed lamp or connector. Lamp may not operate correctly.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email