OBD Guide
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B1240

Start Button Mode Indicator Circuit Short

B1240 is an OBD-II diagnostic trouble code meaning: Start Button Mode Indicator Circuit Short. Common causes: short circuit in wiring harness, wiring damage. Estimated repair cost: $56–167.

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

Symptoms

  • Start button indicator does not work
  • Start button indicator flashing
  • Incorrect display of start button operating modes
  • Problems starting the engine (in rare cases)

Causes

  • Short circuit in wiring harness
  • Wiring damage
  • Start button indicator malfunction
  • Contact corrosion
  • Problems with the control unit

How to Fix

  1. Check the wiring harness for damage
  2. Check the condition of the contacts on the start button
  3. Test the start button indicator
  4. Check continuity with a multimeter
  5. Replace damaged components if necessary

Related codes

B1241B1242B1243

FAQ

What does the B1240 code mean?

B1240 is an OBD-II diagnostic trouble code that indicates: Start Button Mode Indicator Circuit Short

What causes a B1240 error code?

The most common causes of B1240 include: Short circuit in wiring harness; Wiring damage; Start button indicator malfunction; Contact corrosion.

How do I fix a B1240 diagnostic trouble code?

To fix B1240: Check the wiring harness for damage. Check the condition of the contacts on the start button. Test the start button indicator. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1240?

Limited driving only, diagnose soon

How much does it cost to fix B1240?

The estimated repair cost for B1240 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat