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ABS and VSA Lights On, Soft Brake Pedal on 2017 Acura MDX

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Heather Y. · rep 0 · May 22, 4:57 AM · 1 replies · solved · Question

Vehicle: 2017 Acura MDX Technology Package

Hi everyone,

I'm having a serious issue with my 2017 Acura MDX (FWD with Technology Package). This morning, while driving, the ABS warning light and the VSA (Vehicle Stability Assist) warning light both illuminated on my dashboard. Simultaneously, I noticed that my brake pedal feels much softer than usual, almost spongy, and I have to push it down further to get the car to stop.

There are no obvious leaks under the car, and the brake fluid reservoir seems to be at the correct level. I'm really concerned about driving it like this. Has anyone experienced this combination of lights and a soft pedal on their MDX? What could be causing this, and is it safe to drive to a mechanic?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:57 AM

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ClearTheCode admin answer:

When both the ABS and VSA lights illuminate, especially accompanied by a soft brake pedal, it indicates a significant issue within your braking or stability control system. This is a serious safety concern for your 2017 Acura MDX.

Common Causes:

  1. Master Cylinder Failure: A failing master cylinder is a very strong candidate for a soft or spongy pedal. If the internal seals are leaking, brake fluid can bypass the piston, leading to reduced hydraulic pressure and a soft pedal. This can also trigger ABS/VSA lights if the system detects insufficient pressure.
  2. ABS Modulator/Pump Issue: The ABS modulator or pump assembly could be failing. If it's not maintaining proper pressure or if there's an internal fault, it can affect both ABS/VSA function and pedal feel. This would likely trigger specific OBD-II codes related to the ABS system (e.g., C1000 series codes).
  3. Brake Fluid Leak (Internal or External): While you checked for external leaks, an internal leak within the master cylinder or even a very slow, hard-to-spot external leak could lead to air in the system and a soft pedal. Air in the lines is a common cause of sponginess.
  4. Faulty Wheel Speed Sensor: While less likely to cause a soft pedal directly, a faulty wheel speed sensor can trigger ABS/VSA lights. However, the soft pedal suggests a hydraulic issue is also present.

When to see a shop:

  • IMMEDIATELY. Driving with a soft brake pedal and illuminated ABS/VSA lights is extremely dangerous. Your braking performance is compromised, and critical safety systems are disabled. Do not drive the vehicle further than absolutely necessary. If possible, have it towed to a reputable mechanic.

Recommended Steps:

  1. Check Brake Fluid Level Again: Double-check the brake fluid reservoir. Even a slight drop could indicate a leak. If it's low, do NOT just top it off without finding the leak.
  2. Scan for OBD-II Codes: A professional shop will connect an OBD-II scanner capable of reading ABS-specific codes. These codes will be crucial in diagnosing whether the issue is with the master cylinder, ABS pump, or another component.
  3. Professional Inspection: A mechanic will inspect the entire braking system, including the master cylinder, brake lines, calipers, and ABS unit, to pinpoint the exact cause of the hydraulic pressure loss and system warnings.

Given the severity of the symptoms, prioritize getting your MDX to a professional for diagnosis and repair right away.

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