Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
AYC Function, UNDERSTEERING
Understeering is when the vehicle has the tendency to try to continue straight ahead even though the steering wheel has been turned. In the event of understeering, the brake control module (BCBM) sends a request for torque reduction to the engine control module (ECM) via CAN.
In the example above, the steering wheel was turned to the right, but the vehicle tends to continue straight ahead. The SV valve (separation valve) closes, the ESV valve (Electronic Shuttle Valve) opens and the pump starts. The DSTC/ESC system applies the brakes to the right rear wheel by leaving intake valve C2 open and closing the other intake valves (C1, C3 and C4).
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.