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.
DTC P2552: Throttle Actuator Control Module Relay Malfunction: General Description
The electronic throttle control system (ETCS) controls the throttle valve opening. The system is composed of the throttle actuator, the throttle valve, throttle position (TP) sensors A and B, the throttle actuator control module, and the throttle actuator control module relay in the throttle body.
The accelerator pedal position (APP) sensor is operated via the throttle cable to determine the accelerator opening value when the driver presses the accelerator pedal. The accelerator pedal opening value is converted to a signal in the APP sensor, transmitted to the engine control module (ECM)/powertrain control module (PCM), and then transmitted to the throttle actuator control module.
The throttle actuator control module determines the throttle valve target position according to the signal received and operates the throttle actuator to move the throttle valve to the target position. The actual throttle valve position is determined by TP sensors A and B installed in the throttle body.
The ECM/PCM detects the malfunction of the throttle actuator control module relay ON, and a DTC is stored if the serial signal from the throttle actuator control module is input for more than a set time after the throttle actuator control module relay is turned OFF and throttle actuator control module operation is stopped.
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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.
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