Why would the ABS light come on in a car and then not start?

The ABS (Anti-lock Braking System) light coming on and then the car not starting aren't directly related, but the ABS system's failure *could* be a contributing factor in some indirect ways. The light itself is just an indicator of a problem within the ABS system; it doesn't directly prevent the engine from starting. Here's a breakdown of why you might see this combination:

Unlikely Direct Connection: The ABS system doesn't control the engine's starting mechanism. A faulty ABS module won't usually prevent the car from cranking or starting.

Possible Indirect Connections:

* Shared Power/Ground Issue: A problem with the car's electrical system, such as a blown fuse, a corroded connection, or a failing battery, could affect both the ABS system (triggering the light) and the starter motor's ability to crank the engine. This is the most probable explanation.

* Faulty Body Control Module (BCM): The BCM acts as a central control unit, managing various systems in your car. A malfunctioning BCM could affect both the ABS system and other critical functions, including the starting system.

* Immobilizer System Interference (Less Likely): In some cars, if there's a serious electrical problem affecting the communication between different modules (including the ABS), it might accidentally trigger the car's immobilizer system, preventing it from starting. This is less common.

* Low Battery Voltage (Most Likely): A low battery could cause the ABS light to come on (as the system might not have enough power to self-test correctly), and then leave insufficient power to turn the starter motor.

In short: While a faulty ABS system alone *won't* stop your car from starting, the appearance of the ABS light alongside a no-start condition strongly suggests a more general electrical problem, most likely related to the battery, its connections, or a central control module like the BCM. You need to diagnose the underlying electrical problem.

What to do:

1. Check the battery: Test the battery voltage. Is it sufficiently charged? Are the terminals clean and secure?

2. Check fuses: Look in your car's fuse box for blown fuses, especially those related to the electrical system, ignition, or ABS.

3. Have it professionally diagnosed: A mechanic can use diagnostic tools to identify the precise cause of both the ABS light and the no-start condition. Ignoring the problem could lead to more serious and costly repairs.

Don't attempt to start the car repeatedly if it fails to crank, as this can drain the battery further.