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.
Detection Condition
DTC P1780 indicates TCS was not cycled during KOER self-test. Transaxle Control Switch (TCS) is a momentary contact switch that allows driver to cancel overdrive gear. When TCS is pressed, a signal is sent to PCM which then uses the shift solenoids to disengage/disable overdrive gear operation. At the same time, Transaxle Control Indicator Light (TCIL) is illuminated to notify driver that overdrive gear is canceled. When TCS is pressed again, overdrive gear operation is enabled and TCIL is turned off.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.