Error code spn 647, fmi 5

Here is a link that can help you

https://ddcsn-ddc.freightliner.com/cps/rde/xbcr/ddcsn/0111-16.pdf

 

According to the link Buster Cherry provided, you have an engine fan solenoid issue. What is the engine fan doing? Might be the harness grounded out.

 

Is the fan working like normal coming on at certain temperatures, or with the a/c on? Is it staying on constantly? Your harness might be getting moisture inside when it rains and making the code pop up, even if only temporary. Check out this video, the plug may be where moisture is getting in.

 

Typically with an open circuit fault, the fan will stay running constantly and not cycling. The open circuit fault is suggesting that moisture is inside the plug somewhere making it not read correctly. Take the plug loose like in that video, blow it out, and reconnect it. If the fan is operating normally and cycling in and out, don’t worry about it. If it stays on, that plug or that solenoid is your problem probably. Check for moisture first.

 

He checked the voltage with a multi meter, although he didn’t show it in the video. In his case, the plug was working and getting the necessary voltage so the issue was the solenoid. He disconnected the airlines by pushing in the ring so he could put on the new solenoid and reconnected them. Freightliner should have them although I am not sure how much they are. If it dries out and the engine fan runs constantly, then look at replacing it. If it goes back to cycling like it should, then the solenoid is ok, and you may just want to try to keep that plug connector dry and sealed from moisture.

So, in dry weather if the fan runs constantly, you need to replace the solenoid most likely. If it goes back to cycling, everything should be ok. Just seal that plug connector to prevent it in The future.