Technical Description of OBD-II Trouble Code
Bank 2 is Too Rich Off Idle
What does that signify?
This generic trouble code is applicable to fuel injected engines manufactured by most European and Asian carmakers since 2010.
These manufacturers include but are not limited to Volkswagen, Audi, Mercedes, BMW/Mini, Hyundai, Mazda, Kia, and Infiniti.
This code primarily focuses on the air/fuel ratio sensor, commonly known as the oxygen sensor, located in the exhaust. This sensor assists the vehicle’s powertrain control module (PCM) in regulating the amount of fuel injected into the engine. Specifically, the PCM has detected a rich condition, indicating an excessive amount of fuel in the air/fuel ratio. This code is specific to Bank 2, which refers to the cylinder bank that does not include cylinder number 1. The cause of this code can be either a mechanical or electrical circuit fault, depending on the vehicle manufacturer and fuel system.
Troubleshooting steps may vary depending on the manufacturer, type of fuel system, type of mass airflow sensor (MAF), wire colors, and type of air/fuel ratio sensor/oxygen sensor (AFR/O2) and wire colors.
Symptoms
The symptoms associated with a P2190 engine code may include:
Causes
Possible causes for this code to be triggered are:
Diagnostic and Repair Procedures
It is always advisable to check for technical service bulletins (TSB) specific to your vehicle. Your issue may be a known problem with a known solution provided by the manufacturer, which can save you time and money during diagnosis.
First, check if there are any other diagnostic fault codes present. If any of them are related to the fuel or fuel system, address those codes first. Misdiagnosis can occur if this code is diagnosed before thoroughly diagnosing and dismissing any fuel-related system codes.
Next, locate both the air/fuel ratio sensor/oxygen sensor and the mass airflow sensor in your vehicle. Here is an example of a MAF sensor:
Once located, visually inspect the connectors and wiring. Look for any signs of chafing, rubbing, bare wires, burn spots, or melted plastic. Separate the connectors and carefully examine the terminals (metal parts) inside. Check for corrosion, burns, or any green discoloration, which is abnormal compared to the usual metal color. If necessary, use Electrical Contact cleaner or rubbing alcohol and a light plastic bristle brush to clean the terminals. After cleaning, let them air dry and apply some dielectric silicone compound (similar to what is used for light bulb sockets and spark plug wires) where the terminals make contact.
If you have a scan tool, clear the diagnostic trouble codes from memory and check if this code reappears. If it does not, then the issue was most likely related to the connections.
If the code does reappear, you will need to test the voltage signal from the MAF sensor to the PCM. Monitor the MAF sensor voltage using a scan tool. If a scan tool is not available, you can test the signal from the MAF sensor using a digital volt ohm meter (DVOM). With the sensor connected, connect the red voltmeter lead to the MAF sensor signal wire and the black voltmeter lead to ground. Start the engine and monitor the MAF sensor input. As the engine RPM increases, the MAF sensor signal should also increase. Refer to the manufacturer’s specifications for a chart indicating the expected voltage at a given RPM. If the MAF sensor fails this test, replace it and retest.
If the previous tests have passed and the code is still present, monitor the air/fuel ratio sensor/oxygen sensor (AFR/O2). If it consistently indicates a rich running engine, investigate all possible causes of a rich condition, including:
Once again, it is crucial to diagnose any other codes before addressing this one, as issues that trigger other codes can also trigger this code.
