How to fix codes P0171, P0300, P1174
GM has issued a technical service bulletin # 08-06-04-001B to address trouble codes P0171, P0300, P1174 on the following vehicles:
2006-2007 Chevrolet Cobalt, HHR
2006 Pontiac Pursuit (Canada)
2007 Pontiac G5, G6
2006-2007 Saturn ION with 2.4L Engine (VIN B, P – RPO LE5)
P0171 System too Lean (Bank 1)
P0300 Random/Multiple Cylinder Misfire Detected
P1174 Fuel Trim Cylinder Imbalance
The most common cause for these types of trouble codes are vacuum leaks or plugged injectors that deliver too little fuel and cause a lean misfire. GM has determined that plugging injector director plate orifices may be the cause. This condition cannot be corrected by cleaning the injector(s).
GM recommends conducting an injector balance test using the Active Fuel Injector Tester (AFIT), CH-47976. If any injector has a lean condition, replace all four injectors with revised injectors.
After installing the new injectors, GM requires a PCM reprogram with updated software. If you fail to reprogram the PCM, you will have continued problems.
©, 2015 Rick Muscoplat
Posted on by Rick Muscoplat