Possible causes

– Faulty electric throttle control actuator (TP sensor 1 and 2)
– Throttle Position Sensor harness is open or shorted
– Throttle Position Sensor circuit poor connection
– Faulty accelerator pedal position sensor

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P2135 MAZDA Description

Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc. The throttle position sensor responds to the throttle valve movement.

The throttle position sensor has the two sensors. These sensors are a kind of potentiometers which transform the throttle valve position into output voltage, and emit the voltage signal to the Engine Control Module (ECM). In addition, these sensors detect the opening and closing speed of the throttle valve and feed the voltage signals to the ECM. The ECM judges the current opening angle of the throttle valve from these signals and the ECM controls the throttle control motor to make the throttle valve opening angle properly in response to driving condition.

MAZDA Technical Service Bulletins for P2135 code