OBD Guide
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B121B

Keypad Input Switch

B121B is an OBD-II diagnostic trouble code meaning: Keypad Input Switch. Common causes: mechanical damage to the keyboard, poor contact in connectors. Estimated repair cost: $56–167.

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

Symptoms

  • Buttons on the control panel do not work
  • Incorrect operation of the multimedia system
  • Check Engine light comes on

Causes

  • Mechanical damage to the keyboard
  • Poor contact in connectors
  • Open or shorted wiring harness
  • Control unit malfunction

How to Fix

  1. Check the keyboard for mechanical damage
  2. Inspect connectors and contacts for oxidation or damage
  3. Check the integrity of the wiring harness
  4. Test the control unit for errors
  5. Replace faulty components

Related codes

B121AB121CB121D

FAQ

What does the B121B code mean?

B121B is an OBD-II diagnostic trouble code that indicates: Keypad Input Switch

What causes a B121B error code?

The most common causes of B121B include: Mechanical damage to the keyboard; Poor contact in connectors; Open or shorted wiring harness; Control unit malfunction.

How do I fix a B121B diagnostic trouble code?

To fix B121B: Check the keyboard for mechanical damage. Inspect connectors and contacts for oxidation or damage. Check the integrity of the wiring harness. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B121B?

Limited driving only, diagnose soon

How much does it cost to fix B121B?

The estimated repair cost for B121B is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat