My 2000 blazer won't fire up. Codes come up P1351 (Ignition control circuit high voltage) I've replaced rotor, coil, module, fuel pump sending unit, ignition switch. Checked all wires and they are good. I get spark and the fuel pump is working but it won't fire. Reading from module to VCM is 4.7, but the VCM is good. What else can I check as to why this truck won't fire. I've put in $800 of parts and to no avail. I desperately need help

thanks

 

You need to find someone with a Tech2 or Gemini or equivalent scanner to scan your truck. I recently had a similar problem with a 99 Suburban that turned out to be the part of the computer that tells the ignition when to fire as well as a bad module. You may need to reflash the computer. I would recommend spending an hour of labor cost and have a professional diagnose the problem, it will actually save you money and aggravation in the long run. But then again... there are some pretty knowledgeable people on this site. Anyone else?

 

Well the module has been replaced..truck has been scanned and they still can't find the problem. What we can't figure out is why we are getting a 4.7 meter reading to indicate high voltage..it should only be from 1-4..doing a pressure test today to see what that says..they don't seem to think its the computer, but its just getting expensive replacing all these parts to no avail..so still hoping someone out there has had this problem

thanks

 

This code, P1351, triggers at an IC voltage of 4.9V, but yes, the reading should be between 1V and 4V per the diagnostic sheet, P1351 - Ignition Control [IC] Circuit High Voltage. Sounds like you somehow either have a short to voltage that is causing this or your IC control circuit inside the PCM is fried and pushing too much voltage.