OBD Guide
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B1591

Autolamp Delay Decrease Circuit Failure

B1591 is an OBD-II diagnostic trouble code meaning: Autolamp Delay Decrease Circuit Failure. Common causes: open or short circuit in wiring harness, faulty lighting delay relay. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • No headlight turn-off delay
  • Incorrect operation of automatic lighting
  • Flashing headlights when closing doors

Causes

  • Open or short circuit in wiring harness
  • Faulty lighting delay relay
  • Problems with the lighting control unit
  • Contact corrosion
  • Light sensor malfunction

How to Fix

  1. Check wiring harness for damage
  2. Check the lighting delay relay
  3. Diagnose the lighting control unit
  4. Clean or replace corroded contacts
  5. Check light sensor

Related codes

B1590B1592B1593

FAQ

What does the B1591 code mean?

B1591 is an OBD-II diagnostic trouble code that indicates: Autolamp Delay Decrease Circuit Failure

What causes a B1591 error code?

The most common causes of B1591 include: Open or short circuit in wiring harness; Faulty lighting delay relay; Problems with the lighting control unit; Contact corrosion.

How do I fix a B1591 diagnostic trouble code?

To fix B1591: Check wiring harness for damage. Check the lighting delay relay. Diagnose the lighting control unit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1591?

Limited driving only, diagnose soon

How much does it cost to fix B1591?

The estimated repair cost for B1591 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat