Engine-Codes - Mercury - B1240 MERCURY

B1240 MERCURY Code - Start Button Mode Indicator Circuit Short

- Code Popularity: 538 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents

|What are the Possible Causes of the B1240 MERCURY Code?

  • 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 B1240 MERCURY Code?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|B1240 MERCURY code tech notes

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

|What is the cost to diagnose the B1240 MERCURY code?

Labor: 1.0

The cost to diagnose the B1240 MERCURY code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

|What are B1240 MERCURY code possible symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

|What Does the B1240 MERCURY Code Mean?

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.

Start Button Mode Indicator Circuit Short

|Need more information with the B1240 MERCURY code?

Need more information on how to fix the B1240 MERCURY code?
Get Access to Factory Service Manuals

|Need help with a B1240 MERCURY code?

Get the B1240 Mercury code diagnosed by a professional: Find a repair shop in your area