Question

2007 Dodge Ram with engine codes P1128 and p1129, what do the codes mean?

Answer 1

P1129 DODGE - Closed Loop Fueling Not Achieved Bank 2
Read more: https://www.autocodes.com/p1129_dodge.html

P1128 DODGE - Closed Loop Fueling Not Achieved Bank 1
Read more: https://www.autocodes.com/p1128_dodge.html

When the engine is cold and is started or there is a malfunction with the engine, the engine operates in “Open Loop” meaning that the Engine Control Module (ECM) will ignore most of the sensors reading and use predefined parameters set by the factory to control the engine, more specifically the engine’s air/fuel mixture. This "Open Loop" operation allows time for the engine to come up to a normal operating temperature before it starts using the information from the sensors to adjust for driving conditions. Once the engine is warm-up or reach normal operating temperature and there are no engine malfunctions, the ECM will start controlling the engine in "Close Loop", meaning that the ECM will receive the signals from the Oxygen Sensor, Coolant Temperature Sensor, and other engine sensors to control the engine's air/fuel mixture.

There are many probable causes for this code to come up, for example, lack of fuel, low fuel pressure, low engine coolant or bad coolant temperature sensor, wiring connection to other sensors, mechanical problems, and problems with the Powertrain Control Module (PCM).

Start by checking the fuel level, coolant level, fuel pressure, oxygen sensors connector, coolant temperature sensor connector, and Mass Air Flow (MAF) sensor and connector.