OBD Guide

B3874

Wiper Low Speed Relay Circuit

B3874 is an OBD-II diagnostic trouble code meaning: Wiper Low Speed Relay Circuit. Common causes: faulty low speed wiper relay, open or short circuit in wiring harness. Estimated repair cost: $11–56.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$11–56 (est.)

Symptoms

  • Wipers do not work at low speed
  • Wipers only work at high speed
  • Intermittent wiper operation

Causes

  • Faulty low speed wiper relay
  • Open or short circuit in wiring harness
  • Problems with the control signal from the control unit
  • Oxidation of relay contacts or connectors

How to Fix

  1. Check the low speed wiper relay
  2. Inspect the wiring harness for damage
  3. Check relay contacts and connectors for oxidation
  4. Replace relay if necessary
  5. Check the control signal from the control unit

Related codes

Error B3874 by Vehicle Brand

FAQ

What does the B3874 code mean?

B3874 is an OBD-II diagnostic trouble code that indicates: Wiper Low Speed Relay Circuit

What causes a B3874 error code?

The most common causes of B3874 include: Faulty low speed wiper relay; Open or short circuit in wiring harness; Problems with the control signal from the control unit; Oxidation of relay contacts or connectors.

How do I fix a B3874 diagnostic trouble code?

To fix B3874: Check the low speed wiper relay. Inspect the wiring harness for damage. Check relay contacts and connectors for oxidation. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B3874?

Limited driving only, diagnose soon

How much does it cost to fix B3874?

The estimated repair cost for B3874 is $11–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat