Ken K
I'm Awesome
Wow, what a unique animal this one is. I have GM esI and yes, it shows circuit 1807 PPL as class2 serial to the VCM / PCM is on direction only. This is according to "Description and Operation". Cutting the YEL wire to the dash lamp removes any possibility of ground from the EVO/Passlock so that light will never come back on.
Removing VATs completely from the VCM/PCM can only be done by removing that feature using an aftermarket reprogramming device and software.
What if have NEVER seen, was the info in "Vehicle Theft Deterrent (VTD) Description. Down the page for EVO/Passlock is the statement saying that if the correct signal is sent from to the VCM/PCM, fuel will be enabled to allow the engine to run.
But, unlike other Theft Deterrent systems GM has used, normally, if a correct signal is received and the engine is low to run, and class 2 signal from the Passlock module is lost, it will continue to allow for a restart without a signal. The PCM just remembers that everything was cool the last time and it's ok to restart. This one does not! At least it does not say so. I have never seen this.
This one allows starting, but if a signal is not sent or received by the PCM, it will only work the remainder of that ignition cycle. So this signal is constant and if lost while running, it will still run until shut off. So, I can only say that it requires a signal each start up at the PCM.
Did your ($450) expensive purchase fix it by eliminating VATs? Because I see no other way to get around it. None of the 12 diagnostic DTC flow charts shows a 50hz signal. Its just not shown in the text.
Class 2 is 7 volts dc to 0 volt dc. The rate at which it repeats during one second is the frequency I have a J-Tool frequency generator that is used in many diagnostic flow charts from VSS to ABS, but not this one.
Beside, the schematic show the EBCM, PCM, ATC if 4X4 are all on the network. These device see all of the messages sent by any other module on the network. But, class 2 sends an address followed by the message, then repeats if needed. Without a response from a "Live" module on the network, that other module may need or require info, the working module reports it as not working. This does not turn on the check engine light if it's a type 2 code, otherwise not emissions related. Plus, most times, one module is the master. It sends a 'State-of-Health" message every 2 seconds. If no response is received, that module flags the inoperative module as bad. Also the TECH2 can communicate with the EOV/Passlock module
So, each year or model with serial data, apparently works differently in some cases.
Best of luck.
Removing VATs completely from the VCM/PCM can only be done by removing that feature using an aftermarket reprogramming device and software.
What if have NEVER seen, was the info in "Vehicle Theft Deterrent (VTD) Description. Down the page for EVO/Passlock is the statement saying that if the correct signal is sent from to the VCM/PCM, fuel will be enabled to allow the engine to run.
But, unlike other Theft Deterrent systems GM has used, normally, if a correct signal is received and the engine is low to run, and class 2 signal from the Passlock module is lost, it will continue to allow for a restart without a signal. The PCM just remembers that everything was cool the last time and it's ok to restart. This one does not! At least it does not say so. I have never seen this.
This one allows starting, but if a signal is not sent or received by the PCM, it will only work the remainder of that ignition cycle. So this signal is constant and if lost while running, it will still run until shut off. So, I can only say that it requires a signal each start up at the PCM.
Did your ($450) expensive purchase fix it by eliminating VATs? Because I see no other way to get around it. None of the 12 diagnostic DTC flow charts shows a 50hz signal. Its just not shown in the text.
Class 2 is 7 volts dc to 0 volt dc. The rate at which it repeats during one second is the frequency I have a J-Tool frequency generator that is used in many diagnostic flow charts from VSS to ABS, but not this one.
Beside, the schematic show the EBCM, PCM, ATC if 4X4 are all on the network. These device see all of the messages sent by any other module on the network. But, class 2 sends an address followed by the message, then repeats if needed. Without a response from a "Live" module on the network, that other module may need or require info, the working module reports it as not working. This does not turn on the check engine light if it's a type 2 code, otherwise not emissions related. Plus, most times, one module is the master. It sends a 'State-of-Health" message every 2 seconds. If no response is received, that module flags the inoperative module as bad. Also the TECH2 can communicate with the EOV/Passlock module
So, each year or model with serial data, apparently works differently in some cases.
Best of luck.
