OBD Guide
ENFRDEESPT

B2520

High Mount Stop Lamp Circuit Short To Battery

B2520 is an OBD-II diagnostic trouble code meaning: High Mount Stop Lamp Circuit Short To Battery. Common causes: damage to wire harness insulation, oxidation/corrosion of contacts. Estimated repair cost: $22–89.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$22–89 (est.)

Symptoms

  • Additional brake light does not work
  • The brake light is constantly on (when fully closed)
  • BCM memory error

Causes

  • Damage to wire harness insulation
  • Oxidation/corrosion of contacts
  • LED module failure
  • Problems with BCM
  • Mechanical damage to the wiring harness

How to Fix

  1. Visual inspection of the wiring harness in the trunk lid area
  2. Checking resistance and continuity
  3. LED module diagnostics
  4. Circuit power and ground testing
  5. Replacing damaged components

Related codes

B2521B2522B2523

FAQ

What does the B2520 code mean?

B2520 is an OBD-II diagnostic trouble code that indicates: High Mount Stop Lamp Circuit Short To Battery

What causes a B2520 error code?

The most common causes of B2520 include: Damage to wire harness insulation; Oxidation/corrosion of contacts; LED module failure; Problems with BCM.

How do I fix a B2520 diagnostic trouble code?

To fix B2520: Visual inspection of the wiring harness in the trunk lid area. Checking resistance and continuity. LED module diagnostics. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2520?

Do not drive — repair immediately

How much does it cost to fix B2520?

The estimated repair cost for B2520 is $22–89. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat