2018 Outlander SEL - ABS and Traction Control Lights On, Rough Ride

ClearTheCode admin answer:

It's very common for the ABS and Traction Control lights to illuminate together, as both systems rely heavily on wheel speed sensor data. The C0040 code directly confirms an issue with the Right Front Wheel Speed Sensor.

Here's what's likely happening and what to do:

1. Wheel Speed Sensor Issue (C0040):

   • Cause: The wheel speed sensor provides crucial data to the ABS and Traction Control modules. If it's faulty, dirty, or its wiring is damaged, these systems will disable themselves, triggering the warning lights. This is the primary cause of your dashboard lights.
   • Action: Inspect the right front wheel speed sensor and its wiring. Look for obvious damage, corrosion, or dirt accumulation. Often, replacing the faulty sensor resolves the issue. Ensure the new sensor is properly seated and the wiring is secure.

2. Rough Ride:

   • Cause: While a wheel speed sensor won't directly cause a rough ride, the ABS/Traction Control system being disabled might feel different, especially if you're used to its subtle interventions. However, a genuinely rough ride is more indicative of a separate suspension component issue. This could include worn struts, damaged coil springs, failing ball joints, or deteriorated bushings.
   • Action: Have a qualified technician inspect your front suspension components. They will check for:
     • Leaking or worn struts/shocks.
     • Damaged or broken coil springs.
     • Worn control arm bushings or ball joints.
     • Damaged sway bar links or bushings.

When to See a Shop: If cleaning or replacing the wheel speed sensor doesn't clear the C0040 code and the lights remain on, or if the rough ride persists after addressing the sensor, it's time to visit a professional shop. They have specialized diagnostic tools to pinpoint complex electrical issues within the ABS module and can thoroughly inspect suspension components for wear and tear that might not be obvious to the untrained eye. Driving with disabled ABS/Traction Control can compromise safety, especially in adverse conditions, and a compromised suspension can affect handling and tire wear.