2015 duramax 2500HD high country. Code p0722 output sensor we replaced sensor and truck isn’t shifting out of first. And Speedo wasn’t working. Got speedo working but no shifting out of first No broken wires to tcm getting 9 volts at sensor and 9 volts at tcm. Cannot find any wiring schematics for this truck. Checked and brake module and that’s fine also. Fuses look good. Tried hard wiring from battery down to sensor and no change either. Any help would be appreciated. Thank you
Transmission problems -- P0722
- Thread starter Mmacdonald17
- Start date
2015 duramax 2500hd high country. P0700 and p0721 came up and we replaced output sensor now p0722 came on and truck won’t come out of first gear. Looked for 2 days and can’t find any wiring issues. No idea where to go next. Any tips?
I only have ALLDATADIY prints for my 2008 LMM so that's what I can post. You could subscribe to ALLDATADIT or get info direct from GM bot both of those options cost some money.
Well, i just had a 2015 2500HD towed in to me for P0722. This started off as a head scratcher as it came with a brand new VSS installed and a new TCM ordered and on its way. So I check, and rechecked then triple checked EVERYTHING and no go.... Then my GM SET training kicked in and i went down the "personal strategy based diagnostics" rabbit hole. So i fabricated a harness extension to the VSS harness, took a 9/16 bolt and took a cut off wheel and cut many slots in the head to fabricate a test tone ring/reluctor wheel. I then took the sensor out of the transfer case and plugged it into my harness extension. Then I took my slotted head bolt, put it in a drill, turned the key on to the run position and started the drill then put the sensor close to the rotating slots AND VOILA speedometer came alive. I determined that the factory hold down brace was not formed properly and actualy popped the sensor UP and away from the transfer case output shaft tone ring as it was being tightened thus causing an excessive air gap and not allowing any signal to be detected by the TCM. I reformed the hold down brace, bolted it back in, reassembled truck to factory and BIZAM! Everythng operating as intended! ALSO! BE WARNED! ONCE P0722 IS SET, THE SPEEDOMETER WILL BEGIN WORKING USING ABS DATA! You need to be watching TCM live data for Vehicle Speed! If you've got a P0722 and your speedometer works, its using ABS data not VSS data!
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