Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
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2 WD or 4X4?
I personally was wondering (completely inexperienced guess) if it may be the VSS, but when talking with the local dealership I was told that this is not likely the issue since the odometer is still working when the speedometer doesn't.
I am not completely sold on the "parts swapping" as a shop can easily hoomk up a scanner and view live data from various sensors helping to narrow problem down even if no trouble codes set.
What you are initially describing is a failing VSS or vehicle speed senosr. On the 4x4 its mounted to the transfer case. It sends data info to the trans control module to controll shifteing as well as speedometer function. If failing, you could develop the symptoms you describe
No way for me to be 100% without looking at scanner while driving and the problem happens to see if drop in the VSS occurs. It could be the sensor or the trans module or even the PCM ( computer) but from what we have seen and repaired, the higher % goes to a failing VSS ( speed sensor)
One would most likely pay for diagnostic wher they hook up scanner, focus on the VSS signal, drive till problem happens and then confirm bad VSS
Guessing? that is expansive and not correct approach via your symptoms. A VSS is basically an easy fix, not too expensive but best to confirm its bad rather than jumping in and swapping parts
Its a critical sensor. A failing one can cause several different problems to include exactly what you describe.Hoever, one cant rule out another problem so from my end, i have to consider the more common per your symptoms
I agree with odometer but,, due to circuitry in the IPC ( cluster) i am thinking its possibel but cant confirm. if anything they would swap the VSS. If still no go, The IPC is a computer as well. it could have an problem that back feeds the trans control module.
The dealer can perform a reflash of the IPC to attempt to help correct problems like this as well
No, dont go to Ford just yet. I have a 2007 F150 and nothing but problems, hate it, Should have gone Chevy :)
The dealer is 100% incorrect, Scanners view live data, the easiest one to view is the VSS signal. The scanner can even do a record for freeze frame data when problem happens
I am unsure why they are saying this. We travel with scan tool all the time. NO code needs to be set. IMO some techs tend to be at a loss without a code set. try the easy way out.
Yes,, the IPC has known issues and reflash can sometimes correct. It could be bad back feed to TCM from the IPC as 4 computers to include the IPC talk toeach other on a data network.
I just want to walk through this in my mind. Again this is my personal guessing, but I do not think it would be wiring due to the timing or how it occurs (always from a stop). I see no problems with the speedometer at other times. Ignition?? No idea why they said that, but again, the electronic controls on the vehicles....well, I guess anything is possible.
By leaving the truck in drive and coming to a complete stop, what would possibly reset itself that could correct the problem? In turn, I am thinking whatever does could likely be the cause of the problem since it goes from working to not working by simply stopping. Something must change. Does the VSS go "idle" when the vehicle stops?
its very complex. You have 4 computers all talking to each other. the VSS signal goes to the PCM then to VCM then to BCM then to IPC all computers. One mis signal from say the VSS? the trans will not shift correct. the only clue you have is lack of speedo so,, the VSS is first to be monitored on the canner when it happens. The the IPC could? be reading signal wrong from the BCM, or the IPC is acting up and kind of resetting at a stop. Its just too complicated to just write to you. The trans is 100%^ computer controlled.
I lean away from ignition and wiring, I lean to IPC or VSS. cant rule out the trans module TCM.
Wish it was easier. I was simply saying to be told they need to swap out parts is not true, There are tests that can be done and procedures like a reflash that can be done first
I do like the 6 speed from what limited time I have driven it. It shifta smooth, gets better MPG and just seems to allow it to drive much easier. I like it