What Causes Both ABS and Parking Lights to Illuminate?

[LeArya]

Reasons and solutions for both parking light and ABS light illumination: 1. A constantly lit ABS light indicates an anti-lock braking system alert. Normally, this light turns on when the ignition is switched on or the engine is started, as the system enters an automatic detection program. After completing the detection, the light should turn off. If the light does not illuminate when the ignition is switched on, or remains lit without turning off, or lights up while driving, it indicates a system malfunction; 2. If only the ABS warning light is illuminated while driving, it signifies a fault within the ABS system, but the vehicle can still rely on the conventional braking system for braking. It is advisable to have a professional use a diagnostic tool for inspection and repair as soon as possible to determine whether the issue lies with the tone ring, sensor, wiring, etc. If both the ABS warning light and the brake system warning light illuminate simultaneously while driving, it indicates faults in both the ABS and brake systems, leading to altered braking characteristics; 3. In the latter case, it is imperative to stop driving immediately and check the brake fluid level. If the fluid level is normal, it suggests that the ABS system may have malfunctioned, meaning the ABS system's regulation function has failed, leaving only the ordinary braking system operational. This can easily cause the rear wheels to lock up more quickly during braking, leading to skidding. In such situations, drive cautiously and seek repairs as soon as possible.

[OKimberly]

I once experienced a situation where both the ABS and parking brake lights came on simultaneously, which made me sweat with anxiety. Upon inspection, it turned out to be due to low brake fluid level, as both systems rely on hydraulic pressure to function. Another friend of mine encountered an issue where the wheel speed sensor was clogged with mud, causing the ABS to falsely trigger and the parking brake light to illuminate as well. In reality, the most common causes are short circuits in the wiring or blown fuses, especially in older vehicles where wiring tends to deteriorate. Additionally, a malfunction in the electronic parking brake control module can also trigger both warning lights. On one occasion, I also discovered that unstable alternator voltage caused sensor misreporting—using a multimeter confirmed the voltage was fluctuating. Finally, I strongly recommend checking the trouble codes first. With modern vehicles equipped with electronic systems, problems can be deeply hidden, and it's often better to seek a reliable repair shop rather than trying to fix it yourself.

[AlexisDella]

Last month, these two warning lights suddenly came on in my car, which scared me so much that I immediately pulled over. The mechanic told me I was really lucky because this situation could very well be a precursor to a major failure in the braking system. He explained that the ABS light and the handbrake light share certain sensor signals—for instance, a faulty wheel speed sensor could trigger both lights simultaneously. Additionally, insufficient hydraulic pressure in the brake master cylinder could cause the same issue, which might mildly affect braking distance or, in severe cases, lead to complete brake failure. Another possibility was that I often forgot to release the handbrake before driving, causing excessive wear on the handbrake system that affected the ABS circuit. Now, I get the chassis wiring connectors inspected every quarter to prevent minor issues like oxidation and poor contact from leading to bigger problems.

[Hank]

After ten years in auto repair, I've seen countless cases where both the ABS and parking brake lights illuminate simultaneously. The most common scenarios are: First, excessively worn brake pads trigger the sensor wire, indirectly affecting the electronic parking brake system; second, inaccurate wheel speed signals after tire size modifications cause the ABS computer to misdiagnose faults; and another easily overlooked reason—the vehicle's onboard computer software requires an update. Just last week, a customer kept replacing hardware components, only to solve the issue by simply updating the ECU program. I recommend prioritizing diagnostic tools to read fault codes, unlike my client who wasted money replacing three sensors unnecessarily. Remember to regularly check the brake fluid condition—cloudy or degraded fluid can cause hydraulic sensors to give false alarms.