1. Check the obvious: Make absolutely sure the emergency brake lever is fully released. Sometimes it can seem released but isn't quite disengaged. Gently try to move the lever a tiny bit further to release any possible residual tension.
2. Inspect the cable: Look under the car (if you can safely do so) at the emergency brake cable mechanism near the rear wheels. Is there anything visibly obstructing it? Is the cable itself kinked or damaged? This is difficult to see without experience, and you may not even be able to see the cable easily.
3. Try rocking the car: Gently rock the car back and forth. This might help to free up any sticking parts.
4. If it's still locked: Do NOT attempt to drive the car. Driving with the emergency brake engaged is incredibly dangerous and will severely damage the brake system and possibly other components. Call a qualified mechanic or roadside assistance. Explain the situation clearly, mentioning that the emergency brake is fully engaged and the car is immobile.
The most likely causes are:
* Cable seizure: The emergency brake cable may be seized due to rust, corrosion, or lack of lubrication.
* Caliper issue: A rear wheel caliper might be sticking, even if the emergency brake is released. This is less likely to suddenly lock the brakes overnight but possible if it was already partially sticking.
* Mechanical linkage problem: A problem within the emergency brake's linkage mechanism could be causing the problem.
A mechanic will be able to diagnose the precise cause and repair it safely. Do not try to fix this yourself unless you have significant automotive experience.
