OBD Guide
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B1D21

Remote Control Switch Signal Compare Failure

B1D21 is an OBD-II diagnostic trouble code meaning: Remote Control Switch Signal Compare Failure. Common causes: remote control switch malfunction, open or short circuit in wiring harness. Estimated repair cost: $56–167.

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

Symptoms

  • Remote control malfunction
  • Incorrect operation of control functions
  • Check Engine light comes on

Causes

  • Remote control switch malfunction
  • Open or short circuit in wiring harness
  • Problems with the control module
  • Poor contact in connectors

How to Fix

  1. Check the remote control switch for damage
  2. Inspect the wiring harness and connectors for damage
  3. Check voltage and resistance in the circuit
  4. Replace switch or wiring harness if necessary
  5. Reset the error and check if it returns

Related codes

B1D22B1D23

FAQ

What does the B1D21 code mean?

B1D21 is an OBD-II diagnostic trouble code that indicates: Remote Control Switch Signal Compare Failure

What causes a B1D21 error code?

The most common causes of B1D21 include: Remote control switch malfunction; Open or short circuit in wiring harness; Problems with the control module; Poor contact in connectors.

How do I fix a B1D21 diagnostic trouble code?

To fix B1D21: Check the remote control switch for damage. Inspect the wiring harness and connectors for damage. Check voltage and resistance in the circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1D21?

Limited driving only, diagnose soon

How much does it cost to fix B1D21?

The estimated repair cost for B1D21 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat