Bought this Alpha a few weeks ago. Nice ride except it shut down while doing 45 mph on a 8 lane road.
Friend of mine brought over his scanner it showed the error code was P 0601 then the screen switched
to history that said out of 6000 starts it had 1,900 fails. My friend does not know how he got in History.
I would like to know from anyone in here what scanner can I get that will print out the history. So I can
argue the fact that they knew before I bought it, that it was a preexisting problem.

 

This might help. Sounds like a computer failure.
P0601 is a Transmission Control Module (TCM) Read Only Memory (ROM) failure. It is not an emissions device and as such would not be covered under an emissions warranty.

Also, the actions taken when it sets do not include shutting down the vehicle...something else is causing that. Unless the command of 2nd gear makes you think the engine is shutting down because you were in a higher gear?

From the repair manual:

DTC Descriptors
This diagnostic procedure supports the following DTCs:

• DTC P0601 Transmission Control Module (TCM) Read Only Memory (ROM)
• DTC P0602 Transmission Control Module (TCM) Not Programmed
• DTC P0603 Transmission Control Module (TCM) Long Term Memory Reset
• DTC P0604 Transmission Control Module (TCM) Random Access Memory (RAM)
• DTC P062F Transmission Control Module (TCM) Long Term Memory Performance
• DTC P1621 Transmission Control Module (TCM) Long Term Memory Performance

Conditions for Running the DTC
The TCM runs the program to detect an internal fault when the engine is running. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.

Conditions for Setting the DTC
The TCM has detected an internal malfunction.

Action Taken When the DTC Sets

• The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
• The TCM commands second gear.
• The TCM commands maximum line pressure.
• The TCM inhibits torque converter clutch (TCC).
• The TCM freezes transmission adaptive functions.
• The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
• The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
• The TCM stores DTC P0601, P0602, P0603, P0604 or P062F, P1621 in TCM history.

 

Well the dealership where I bought the H3 is denying responsibility of it being a known problem prior to my purchase. The history report I seen said out 6000 starts the system failed 1900 times. So they took to service and came back saying nothing was wrong, The work order report stated BAD E.C.M. I asked to show me the history... they handed me the keys and said "sorry it's been cleared, Have a nice day"

 

If the tcm is reporting an internal fault it can cause the high speed lan line(communication) to go down. In turn that can cause the ecm to go offline and cause engine stall. A simple power down and restart corrects issue for the time being but will fail again. Simply put repair what you know is broken and in most cases especially with modules it will correct your issue. No brainer to replace a module with an internal fault code as long as wiring is good to module.

 

Forgive me if I need a helmet on this HUMTECH... How can I make it duplicate that fault? Would tell me what I need to know if the O.B.D. scanner is on?
Thanks everyone for your replies this has me feeling like a deer in headlights.
[IMG]www.hummerforums.com/forum/attachment.php?attachmentid=9549&stc=1&d=146526541 1[/IMG]

 

The only way to induce the fault is to drive it and let it happen. You could run new power, grounds and data lines to tcm but in my experience internal fault codes have always come down to their description as an internal failure. Hardest part of my job is inducing intermittent failures and finding a concrete solution.

 

If it has a remote starter, aftermarket radio with can bus interface or a gps tracker, ign disable device installed those would all be suspect to your issue as well. Any device linked into data lines can cause issues like these.

 

Nothing added, everything I see is stock from the factory except the tires.

 

No remote start, factory radio monsoon,no gps or tracker no ign disable device