DSP5 Quit working

[JeromeGTO5.7]

Guys I got a switch here that i kicking my tail. It worked for a few months,then quit working. on the scan tool it shows up as the tune is unknown instead of nonDSP like i thought it would. and the switch voltage shows 0.

And i can get 5.1 volts on the signal side and it works through the ground
wire as well Which would indicate to me that the wiring is all intact I even cut the wires and spliced a new switch, and it didnt make a difference. I full flashed with the DSP5 files again just to see if that made any difference.

Is there any way this Could be a bad circuit in the ECM? Id love to hear anybodys ideas or suggestions of what to check.

cheers, Jerome

[GMPX]

The scantool response seems quite odd.
If you can check the voltages at the ECM with a voltmeter (rather than the scantool) that might help determine if the switch is still good. You should see the voltage at the ECM change (by about 1 volt) for each DSP tune selected.

[JeromeGTO5.7]

Thats wat was so strange, it would switch the voltages according to the voltmeter, but the scan tool wouldnt show anything ant the truck was definately not switching tunes. Have you ever heard of that circuit going bad in the ecm?

[GMPX]

No I haven't, but that doesn't mean it can't happen, I would be very surprised though if the ECM input has failed.
The only thing I can think of is somehow a non DSP program has been flashed in to the ECM again. Without DSP installed in the ECM the switch voltage will report 0 and the tune will show unknown because the value the scantool gets back from the ECM won't line up to what the DSP tunes would indicate.
Pretty easy to confirm this, just check the ECM info through the Tune program (Go - Flash > Show PCM info) and confirm the OS number shown is a DSP one.

Cheers,
Ross

[JeromeGTO5.7]

Well i checked that and the DSP5 tune was in there, but i full flashed it again with the DSP files to make sure and it was the same situation. Its on a friends truck so i guess when he can spare his truck ill work with it some more. But like you i really wouldnt think it would be the ECM. but im kinda running out of options. I know nothing about those ECMs. Is there any way one part of it can go bad and all the rest work normally?

Thanks, Jerome

[lakingslayer]

Which version of the Scan tool are you using? I'm having a similar issue with my friends '01 truck. I'm using the March 30 release (I can't remember the version number).

[JeromeGTO5.7]

Well i was running the october version but i updated now and am on the march 30 version but have not had a chance to check it out since then but it kinda kicked my tail before but when i get a chance ill check it out again i about decided its the ecm but that pretty strange

[lakingslayer]

It was just a thought. Looks like you probably have a hardware issue.

[JeromeGTO5.7]

Uh huh i guess so have you had any luck with the one your working with?

[vortecfcar]

That error is a signal that the tune is set to serial switchability instead of hardwired if I recall.

Table A0146

Hope this helps.

Nick