If you are using the original ez robot ping the colour of the wires makes it easier for conformity for tutorials and the user (especially new users) .... You really don't need help here just swap the wires (trigger and echo) and that's it... Probably got accidentally swapped during assembly... To be honest as long as the ping is plugged into the correct ports it doesn't really matter what colour the wires are...

P.S.... if you're talking about the new model ping that uses only 3 wires.... It uses the same pin for trigger and echo... plug n' play so just plug it directly into one digital port

@Richard R: thanks sincerely for your fast reply. As you say, that's probably what happened. However, I must be 100% certain and confirm the error is not in the manual.

@DJ Sures: is the error on the Ultrasonic detector or the manual?

Nothing bad will happen if the trigger and echo are reversed. The ping just won't work but it won't break .... Just switch the wires... However, I will let @DJ handle this as this is the best advice I can give you....

@Richard R: Thanks for the good advice.

I followed the color code in the online manual and changed the Ultrasonic detector cables to match echo and trig.