AutoCodesFord – B1240 Ford

B1240 Ford Code - Start Button Mode Indicator Circuit Short

Quick Answer

The Body Control Module (BCM) uses a Field Effect Transistor (FET) as circuit protection for the start/stop switch indicator and as an electronic switch to turn the start/stop switch indicator on and off. Common causes include Faulty Start/Stop Switch Indicator, Start/Stop Switch Indicator harness is open or shorted, Start/Stop Switch Indicator circuit poor electrical connection. 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 Ford indicates Start Button Mode Indicator Circuit Short.
Common causes
Common causes include Faulty Start/Stop Switch Indicator, Start/Stop Switch Indicator harness is open or shorted, Start/Stop Switch Indicator circuit poor electrical connection.
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.
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Code Popularity 8,255
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Mar 04, 2019
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Code B1240 Ford Description

The Body Control Module (BCM) uses a Field Effect Transistor (FET) as circuit protection for the start/stop switch indicator and as an electronic switch to turn the start/stop switch indicator on and off. The FET receives fused battery voltage from BCM. When the start/stop switch is pressed a voltage and ground signal are sent to the BCM. When the vehicle enters RUN or START mode, the BCM forward biases the FET which provides voltage to the amber LED in the start/stop switch, illuminating the word ENGINE.
OBDII Code B1240 Ford - Start Button Mode Indicator Circuit Short - AutoCodes.com
B1240 Ford Code - Start Button Mode Indicator Circuit Short

What are the Possible Causes of the DTC B1240 Ford?

  • Faulty Start/Stop Switch Indicator
  • Start/Stop Switch Indicator harness is open or shorted
  • Start/Stop Switch Indicator circuit poor electrical connection
  • Faulty Body Control Module (BCM)

How to Fix the DTC B1240 Ford?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1240 Ford code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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.

Frequently Asked Questions about B1240 Ford Code

1. What does the OBDII code B1240 mean for a Ford vehicle?

B1240 indicates a Start Button Mode Indicator Circuit Short, meaning there’s an electrical issue in the circuit responsible for illuminating the start button mode indicator light.

2. What are the common symptoms of code B1240?

Symptoms include the start button mode indicator light not functioning, intermittent illumination, or other dashboard electrical issues.

3. What causes the B1240 code in Ford vehicles?

The code is typically caused by a short circuit, damaged wiring, a faulty start button mode indicator, or a problem with the associated control module.

4. Can a blown fuse cause code B1240 on a Ford?

Yes, a blown fuse in the circuit can interrupt power flow and trigger the B1240 code.

5. How do you diagnose the B1240 code on a Ford vehicle?

Diagnosis involves inspecting the wiring and connectors for damage, checking the start button mode indicator light, and testing the control module for faults.

6. Is it safe to drive with the B1240 code active?

While the vehicle may still start, the code could indicate a larger electrical issue that should be addressed to avoid further complications.

7. How do you fix a B1240 code on a Ford vehicle?

Repairs may include replacing damaged wiring, fixing shorts, replacing the start button mode indicator light, or repairing/replacing the control module.

8. How much does it cost to repair code B1240 on a Ford?

Repair costs vary depending on the issue but could range from $50 for simple wiring repairs to several hundred dollars for control module replacement.

9. Can I clear the B1240 code without fixing the problem?

Clearing the code without addressing the root cause may temporarily remove the error, but the code will likely return.

10. What tools are needed to troubleshoot code B1240 on a Ford?

You’ll need an OBDII scanner, a multimeter, and basic tools for inspecting and repairing wiring and electrical components.

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