C0300 code after longtube install

[Crimson6.2L]

I installed my longtubes over the weekend and decided to check the codes with my scanner and seen I had a C0300 code. Says rear propshaft speed sensor. From what I’ve googled. Never had this code before the longtubes so I’m assuming I did something during the install. What exactly is this sensor and where is it located?

[Dan Martin]

Sounds like a trans input or output speed sensor.


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[davester]

It should be at the rear of the transmission for 2wd, or the rear of the transfer case for 4wd.

 

I'd be looking around the headers/exhaust to see if any wiring has come close and melted, or if something was pulled or if the connector was unplugged  and not fully reinserted.

[Crimson6.2L]

2 hours ago, davester said:

It should be at the rear of the transmission for 2wd, or the rear of the transfer case for 4wd.

 

I'd be looking around the headers/exhaust to see if any wiring has come close and melted, or if something was pulled or if the connector was unplugged  and not fully reinserted.

I checked and didn’t find anything. Run the code reader again after I looked and it was gone. Actually did it twice and wasn’t there either time. 

[NWdirt]

Sorry this is off topic but I'm looking to install long tube headers on my 6.2. Did you more noise in the cab at freeway speeds? Thanks.

[Crimson6.2L]

1 hour ago, NWdirt said:

Sorry this is off topic but I'm looking to install long tube headers on my 6.2. Did you more noise in the cab at freeway speeds? Thanks.

There’s definitely more noise. I went catless as well. It does have drone nothing crazy but definitely noticeable. I can also hear what sounds like rushing air under the floorboard at light acceleration. It doesn’t sound like a tick or ping like people say with a leak. I don’t have leaks at the collectors or where the y pipe goes together that i can feel or see. I also re torqued the header bolts after 3 heat cycles and don’t see spot or any evidence of a leak there either. May be normal this is my first set so I’m not sure what’s normal.

[NWdirt]

10 minutes ago, Crimson6.2L said:

There’s definitely more noise. I went catless as well. It does have drone nothing crazy but definitely noticeable. I can also hear what sounds like rushing air under the floorboard at light acceleration. It doesn’t sound like a tick or ping like people say with a leak. I don’t have leaks at the collectors or where the y pipe goes together that i can feel or see. I also re torqued the header bolts after 3 heat cycles and don’t see spot or any evidence of a leak there either. May be normal this is my first set so I’m not sure what’s normal.

Excellent description. Thank you. From what you describe it sounds similar to my old 5.7 OBS chevy with headers. Thought 2014+ body style might different. 

[newdude]

16 hours ago, Crimson6.2L said:

I installed my longtubes over the weekend and decided to check the codes with my scanner and seen I had a C0300 code. Says rear propshaft speed sensor. From what I’ve googled. Never had this code before the longtubes so I’m assuming I did something during the install. What exactly is this sensor and where is it located?

 

Was this the only code?  Its not coming up as a good code in the GM service manual.  Doesn't come up in the master DTC list either for a K2 Sierra.