Bluetooth Car (Arduino)

// Motor Port
int E1 = 6;
int M1 = 9;
int E2 = 10;
int M2 = 11;

void setup() {
    Serial.begin(9600);
    pinMode(M1, OUTPUT);
    pinMode(M2, OUTPUT);
}

void loop() {
    if (Serial.available()) {
        char input = Serial.read();

        if(input == '4') {
            turnLeft();
        } else if (input =='8') {
            goAhead();
        } else if (input =='6') {
            turnRight();
        } else if (input =='2') {
            goBack();
        } else if(input == '5') {
            stopTurning();
        }

    }

    // goAhead();
    // delay(2000);
    // turnLeft();
    // delay(2000);
    // turnRight();
    // delay(2000);
    // goAhead();
    // delay(2000);

}

void goAhead() {
    stopTurning();
    analogWrite(E1, 191);
    analogWrite(M2, 191);
}

void goBack() {
    stopTurning();
    analogWrite(M1, 191);
    analogWrite(E2, 191);
}

void turnLeft() {
    stopTurning();
    analogWrite(E1, 0);
    // analogWrite(M1,191);
    analogWrite(M2, 191);
}

void turnRight() {
    stopTurning();
    analogWrite(E1, 191);
    // analogWrite(E2, 191);
    analogWrite(M2, 0);
}

void stopTurning() {
    analogWrite(M1,0);
    analogWrite(M2,0);
    analogWrite(E1, 0);
    analogWrite(E2, 0);
}