What does code P1566 mean?

Q: What does code P1566 mean?

Cruise Control Main Switch Circuit Malfunction. P1566 on a Toyota means the engine control module (ECM) has detected an abnormal voltage signal from the cruise control main switch circuit, which is the dash-mounted on/off switch for the cruise system. The ECM expects a specific voltage pattern when the switch is pressed and released, and it flags this code when the signal stays outside the expected range for too long.

DTC codes / Toyota codes / P1566

P1566 · ToyotaCruise Control Main Switch Circuit Malfunction

P1566 on a Toyota means the engine control module (ECM) has detected an abnormal voltage signal from the cruise control main switch circuit, which is the dash-mounted on/off switch for the cruise system. The ECM expects a specific voltage pattern when the switch is pressed and released, and it flags this code when the signal stays outside the expected range for too long.

SystemPowertrain

Code typeToyota specific

SeverityLow

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Guidance is general and written for Toyota vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.