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Home / DTC / B1741 — Turn signal(LH) bulb outage

B1741 — Turn signal(LH) bulb outage

Detailed page for trouble code B1741.

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22,491specific
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Code

B1741

MITSUBISHI B — Body

Turn signal(LH) bulb outage

Brand: MITSUBISHI
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Burned-out/failed turn signal bulb (LH)
  • Poor contact or corrosion in bulb socket
  • Open or short in wiring harness to LH turn signal
  • Faulty ground connection for LH lamp circuit
  • Blown fuse or defective flasher/relay (if used)
  • Faulty Body Control Module (BCM) / lamp control circuit

Symptoms

  • Left turn signal does not illuminate or does not flash
  • Turn signal indicator may show an error or remain off on dash
  • Hazard lights may behave abnormally when LH circuit is affected
  • Intermittent operation or only works when bulb/socket is wiggled

What to check

  • Visually inspect LH turn signal lamp for a burned filament or damaged LED module
  • Check bulb seating and socket for corrosion, bent contacts, or moisture
  • Inspect wiring and connector for damage, pin corrosion, or loose terminals
  • Verify relevant fuses and any turn-signal relay/flasher (if vehicle uses one)
  • Use a scan tool to confirm B1741 and check for additional related codes
  • Confirm ground integrity at lamp body and associated chassis ground point

Signal parameters

  • When turn signal is activated the lamp socket should receive battery voltage (~11–14.5 V) in a pulsed pattern (flash rate ~1–2 Hz)
  • Bulb filament shows continuity (low resistance) when measured with multimeter; an open reading indicates a failed bulb/LED module
  • Voltage at socket should collapse to near 0 V when circuit is off; persistent voltage may indicate short to power

Diagnostic algorithm

  1. Confirm stored code and any freeze-frame or related codes with a scan tool; note whether code is current or historic
  2. Reproduce fault: activate left turn signal and observe lamp behavior and dash indicator
  3. Visually inspect bulb and socket; remove bulb and inspect filament and contacts for damage or corrosion
  4. Install a known-good replacement bulb (or temporarily swap with RH bulb) to verify if lamp lights; if lamp works, replace the bulb
  5. With turn signal ON, measure voltage at the lamp socket pin(s): verify pulsed battery voltage and good ground. If no voltage present, proceed upstream
  6. Check continuity between lamp socket and BCM (or lamp relay) to identify open circuit; wiggle harness to look for intermittent faults
  7. Inspect and test associated fuses, relays, and ground points; repair or replace as needed
  8. If wiring and lamp are good but code persists, inspect BCM connector for corrosion or damaged pins; check for diagnostic trouble codes indicating BCM faults or network communication errors
  9. After repairs, clear codes with scan tool and retest operation for several cycles; verify code does not return

Likely causes

  • Burned-out bulb or poor bulb-to-socket contact
  • Corroded or damaged socket wiring/connector
  • Open circuit in harness between BCM and LH lamp
  • Failed bulb detected after replacing with LED without load resistor

Fault status

⚠️ Status
BCM detected an open/outage in the left-hand turn signal circuit; lamp not providing expected load or voltage signature.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B1740 B1742 B1761 U0155
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

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Code

B1741

Other B — Body

Mirror Passenger Vertical Switch Circuit Failure

Brand: Other
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Burned-out/failed turn signal bulb (LH)
  • Poor contact or corrosion in bulb socket
  • Open or short in wiring harness to LH turn signal
  • Faulty ground connection for LH lamp circuit
  • Blown fuse or defective flasher/relay (if used)
  • Faulty Body Control Module (BCM) / lamp control circuit

Symptoms

  • Left turn signal does not illuminate or does not flash
  • Turn signal indicator may show an error or remain off on dash
  • Hazard lights may behave abnormally when LH circuit is affected
  • Intermittent operation or only works when bulb/socket is wiggled

What to check

  • Visually inspect LH turn signal lamp for a burned filament or damaged LED module
  • Check bulb seating and socket for corrosion, bent contacts, or moisture
  • Inspect wiring and connector for damage, pin corrosion, or loose terminals
  • Verify relevant fuses and any turn-signal relay/flasher (if vehicle uses one)
  • Use a scan tool to confirm B1741 and check for additional related codes
  • Confirm ground integrity at lamp body and associated chassis ground point

Signal parameters

  • When turn signal is activated the lamp socket should receive battery voltage (~11–14.5 V) in a pulsed pattern (flash rate ~1–2 Hz)
  • Bulb filament shows continuity (low resistance) when measured with multimeter; an open reading indicates a failed bulb/LED module
  • Voltage at socket should collapse to near 0 V when circuit is off; persistent voltage may indicate short to power

Diagnostic algorithm

  1. Confirm stored code and any freeze-frame or related codes with a scan tool; note whether code is current or historic
  2. Reproduce fault: activate left turn signal and observe lamp behavior and dash indicator
  3. Visually inspect bulb and socket; remove bulb and inspect filament and contacts for damage or corrosion
  4. Install a known-good replacement bulb (or temporarily swap with RH bulb) to verify if lamp lights; if lamp works, replace the bulb
  5. With turn signal ON, measure voltage at the lamp socket pin(s): verify pulsed battery voltage and good ground. If no voltage present, proceed upstream
  6. Check continuity between lamp socket and BCM (or lamp relay) to identify open circuit; wiggle harness to look for intermittent faults
  7. Inspect and test associated fuses, relays, and ground points; repair or replace as needed
  8. If wiring and lamp are good but code persists, inspect BCM connector for corrosion or damaged pins; check for diagnostic trouble codes indicating BCM faults or network communication errors
  9. After repairs, clear codes with scan tool and retest operation for several cycles; verify code does not return

Likely causes

  • Burned-out bulb or poor bulb-to-socket contact
  • Corroded or damaged socket wiring/connector
  • Open circuit in harness between BCM and LH lamp
  • Failed bulb detected after replacing with LED without load resistor

Fault status

⚠️ Status
BCM detected an open/outage in the left-hand turn signal circuit; lamp not providing expected load or voltage signature.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

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