× Auto Repair Pros Member Benefits TechHelp Knowledge Base Forums Resources My iATN Marketplace Chat Pricing About Us Join Industry Sponsors Video Members Only Repair Shops Auto Pro Careers Auto Pro Reviews
Join Now
International Automotive Technicians Network

P0128 Diagnostic Trouble Code Discussion for September 2012

Thermostat System Malfunction


Note: This is a professional automotive technician's resource.
Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder.

Trouble Ticket Help Requests for DTC P0128
Help Request Posted
2006 Hummer H3 3.5L Poor Idle Quality, Misfire, MIL Lamp on VIN: 5GTDN13636
P0128: Engine Coolant Temperature Below Thermostat Regulating Temperature. I am having trouble finding a definitive answer to why this vehicle has a misfire on cyl #2 at an idle. The code I have is for a random misfire but watching it on the modis shows cyl #2 missing all the time at an idle. I swapped the ignition coils, swapped the...
September 28, 2012
2006 Hummer H3 3.5L Poor Idle Quality, Misfire, MIL Lamp on VIN: 5GTDN13636
P0128: Engine Coolant Temperature Below Thermostat Regulating Temperature. I am having trouble finding a definitive answer to why this vehicle has a misfire on cyl #2 at an idle. The code I have is for a random misfire but watching it on the modis shows cyl #2 missing all the time at an idle. I swapped the ignition coils, swapped the...
September 29, 2012