Engine-CodesGeneric – B1240

B1240 Code - Start Button Mode Indicator Circuit Short

Quick Answer

The B1240 code indicates a problem with the start button mode indicator circuit, specifically a short circuit. Common causes include Faulty start button mode indicator, Short circuit in the wiring of the start button circuit, Corrosion or damage to the wiring harness. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
B1240 indicates Start Button Mode Indicator Circuit Short.
Common causes
Common causes include Faulty start button mode indicator, Short circuit in the wiring of the start button circuit, Corrosion or damage to the wiring harness.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Aug 30, 2024
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Code B1240 Description

The B1240 code indicates a problem with the start button mode indicator circuit, specifically a short circuit. This circuit is responsible for indicating the current mode of the start button, such as whether the vehicle is in accessory mode, on mode, or off mode. When this circuit is shorted, it can affect the accuracy of the mode indicator on the start button, potentially leading to confusion for the driver and affecting the vehicle's overall performance.

OBDII Code B1240 - Start Button Mode Indicator Circuit Short
B1240 Code - Start Button Mode Indicator Circuit Short

Common Causes of B1240

  1. Faulty start button mode indicator
  2. Short circuit in the wiring of the start button circuit
  3. Corrosion or damage to the wiring harness
  4. Issues with the start button control module
  5. Electrical interference or poor connections

Symptoms of B1240

  1. Start button indicator not lighting up or displaying incorrect mode
  2. Vehicle not starting or difficulty starting
  3. Erratic behavior of the start button
  4. Dashboard warning lights related to the start button system
  5. Loss of power or performance issues

How to Fix B1240

  1. Diagnose the exact cause of the short circuit using a multimeter and wiring diagrams
  2. Inspect the start button mode indicator and wiring for any visible damage or corrosion
  3. Repair or replace any damaged wiring or components
  4. Reset the start button system and clear the diagnostic trouble codes
  5. Test the start button system to ensure proper operation

Cost to Fix B1240

The cost of repairing a B1240 code related to the start button mode indicator circuit short can vary depending on the specific cause of the issue and the extent of the repair needed. On average, the cost can range from $100 to $300 for parts and labor. However, it's important to note that labor rates at auto repair shops can vary, so it's recommended to get a detailed estimate from a professional technician.

Tech Notes for B1240

B1240:11 Start Button Mode Indicator Circuit Short to Ground
B1240:15 Start Button Mode Indicator Circuit Short to Battery or Open

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Code B1240 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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