Mopar rough idle when cold
Owners of some 2008-2010 Chrysler 300 Charger/Magnum vehicles may experience a rough idle upon startup when temperatures are below 50 degrees Fahrenheit. This condition most likely happens during the summer and fall seasons when summer blend fuels are in use. The condition is not noticeable after the engine warms to operating temperature.
To correct this condition the PCM software was changed to add additional fuel and increase spark advance during the warm-up cycle.
Using a scan tool (wiTECH) with the appropriate diagnostic procedures available in TechCONNECT, verify that all engine systems are functioning as designed. If DTCs are present, record them and repair as necessary before proceeding further.
Reprogram the PCM with the latest software. The wiTECH software level must be at release 10.04 or higher. StarMOBILE desktop client may also be used to perform this procedure.
Follow the detailed service procedures available in DealerCONNECT/TechCONNECT. Refer to Group 8 – Electrical > Electronic Control Modules – Service Information > Module – Powertrain Control > Standard Procedures > PCM/ECM Programming – Gas.
After PCM reprogramming, clear any DTCs that may have been set in other modules due to reprogramming. The wiTECH application will automatically present all DTCs after the flash and allow the tech to clear them.
Type the neecessary information on the Authorized Modification Label and attach it near the VECI label.