Engine Light & Error Code P0502
 

During my last trip to some local fire roads my check engine light came on. At first nothing seemed to be wrong, until I tried to engage the rear Locker and the light just blinked for like 15 seconds and no go (Ofcourse truck on 4Lo). On my way home I noticed cruise control would not work either.

Onstar diagnosed code P0502. And described the things I experienced; they recommended to take it to the dealer, which I did. Unfortunately by the time I got it to the dealer, the light was gone and everything was back to normal, including the rear locker operation.

After a few days @ Cerritos Hummer I got a call from my service rep and he said the tech could not find anything wrong. He said that if the vehicle was driven on a terrain "it may not have liked" and the wheels spin that this would happen. Ofcourse I called BS, in 20 years of wheeling I have never heard such ridiculous statement, I almost felt like it was a Mazda service rep speaking to me.

Anyway, sorry for the long story, I am meeting with the service Manager tomorrow to figure this thing out. I was just wondering if anyone else has had this problem and if it ever happened again or if it was resolved.

Thanks.

Re: Engine Light & Error Code P0502
 

P0502 is a vehicle speed sensor code. Not very common. Have you noticed any odd operation of the spedometer? Maybe there was moisture in the connector, it's on the back of the t-case. No way to diagnose a problem if it is working properly.

Re: Engine Light & Error Code P0502
 

The problem only happened as described. the speedo worked fine. Dealer thinks it was just a fluke and that it probably would not happen again... we'll see.