Start Button Mode Indicator Circuit Short
Table of contents
B1240 Possible Causes
- 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 do I fix code B1240?
Check 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.
Tech Notes
- B1240:11 Start Button Mode Indicator Circuit Short to Ground
- B1240:15 Start Button Mode Indicator Circuit Short to Battery or Open
Cost of diagnosing the B1240 code
The cost of diagnosing the B1240 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B1240 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.