Fig 1: Electronic Throttle System - Schematic Diagram

Courtesy of KIA MOTORS AMERICA, INC.

FAIL-SAFE MODE

FAIL-SAFE

Mode	Description	Symptom	Possible Cause
MODE 1	FORCED ENGINE SHUTDOWN	Engine stop	ETC system can't proceed reliable algorithm procedure Fatal PCM internal programming error Faulty intake system or throttle body
MODE 2	FORCED IDLE & POWER MANAGEMENT	Forced idle state controlled by fuel quantity regulation and ignition timing adjustment	ETC system can't control engine power via throttle device Disabled throttle control or broken throttle position information
MODE 3	FORCED IDLE	Forced idle state and no response for accelerator activation	No information about the accelerator position Malfunctioning APS 1 and 2, faulty A/D converter or internal controller
MODE 4	LIMIT PERFORMANCE & POWER MANAGEMENT	Engine power is determined by accelerator position and idle power requirement (Limited vehicle running)	ETC system can't securely control engine power
MODE 5	LIMIT PERFORMANCE	Engine power varies with accelerator position, but driver perceives lack of engine power. MIL ON (Normal vehicle running)	Not reliable accelerator position signal or bad maximum power generation Faulty APS, ignition voltage or internal controller
MODE 6	NORMAL	Normal

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.

Safety Warning

Schematic Diagram