OBD Guide

P1805

Stop Lamp Switch

P1805 is an OBD-II diagnostic trouble code meaning: Stop Lamp Switch. Common causes: faulty brake light sensor, open or short circuit in wiring. Estimated repair cost: $6–28.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$6–28 (est.)

Symptoms

  • Cruise control doesn't work
  • Problems starting the engine (on some models)
  • Check Engine Light Is On
  • Incorrect operation of the ABS system
  • Brake lights do not turn on or are constantly on

Causes

  • Faulty brake light sensor
  • Open or short circuit in wiring
  • Oxidized contacts in connectors
  • Problems with the brake pedal
  • Engine control unit malfunction

How to Fix

  1. Check the operation of the brake lights
  2. Inspect the sensor wiring and connectors
  3. Check the brake light sensor with a multimeter
  4. Replace the faulty sensor if necessary
  5. Check and clean contacts in connectors

Related codes

FAQ

What does the P1805 code mean?

P1805 is an OBD-II diagnostic trouble code that indicates: Stop Lamp Switch

What causes a P1805 error code?

The most common causes of P1805 include: Faulty brake light sensor; Open or short circuit in wiring; Oxidized contacts in connectors; Problems with the brake pedal.

How do I fix a P1805 diagnostic trouble code?

To fix P1805: Check the operation of the brake lights. Inspect the sensor wiring and connectors. Check the brake light sensor with a multimeter. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1805?

Do not drive — repair immediately

How much does it cost to fix P1805?

The estimated repair cost for P1805 is $6–28. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat