P2190 OBD-II Trouble Code: System Too Rich at Idle Bank 2

P2190 code definition

System Too Rich at Idle Bank 2

What the P2190 code means

This code indicates there is too much fuel in relation to air (air/fuel ratio) in bank 1 at idle only. Bank 1 is the set of cylinders in an engine that does not contain the number one cylinder. The set of cylinders containing the number one cylinder is referred to as bank 1.

What causes the P2190 code?

A variety of failures can cause this condition. Most often it will be a misfire that sends unburned fuel into the exhaust system. The term misfire is a condition where fuel is injected into a cylinder with the expectation that it will be lit by a spark from the ignition system. If the ignition system fails to create a spark at the spark plug, the injected fuel will not burn and will be pushed out of the cylinder into the exhaust. There are numerous parts in the ignition system that can fail and create this condition.

Leaking fuel injectors can create this condition as well, normally to a lesser degree. The nature of fuel injector failures will result in a mild condition indicated by this code, or result in other more apparent drivability symptoms that will be more obvious to the driver. Clogged fuel injectors are common in older vehicles and could set this code but is less likely.

What are the symptoms of the P2190 code?

Since most vehicles do not idle for extended periods of time, it is likely the owner will not experience any symptoms. A more observant owner may notice loss of power, slight hesitation or a rough idle.

This code is often set along with several other codes that will exhibit symptoms. In some circumstances where the use of a vehicle requires extended idling, the problem this code is reporting will likely result in the fouling of the spark plug for the affected cylinder. The result will be a misfire while idling and possible misfires while driving.

How does a mechanic diagnose the P2190 code?

A mechanic should begin by scanning the vehicle for all codes. If there are other codes present that can contribute to this code, they should be addressed first. Once it is determined this code needs to be addressed, the mechanic should check scan data looking for clues to point him in the direction of the problem.

Some clues to look for are:

• misfire counters
• fuel trims attempting to limit the amount of fuel injected
• possible O2 sensor failures

A quick check of all other components the PCM uses to calculate air fuel ratio is necessary.

Common mistakes when diagnosing the P2190 code

A thorough understanding of the various conditions that cause air fuel mixture problems is vitally important for the diagnosis of codes such as this. Several seemingly unrelated systems can create the conditions to set this code. A mechanic needs to be well versed in the operation of all of these systems and their interaction with each other to accurately diagnose this code:

Ignition system:

• Spark plugs
• Spark plug wires
• Ignition coil or coils
• Wiring harness

Fuel injectors:

• Injector driver in the PCM
• Poor electrical connection in the injector's electrical connector (common)
• Damaged wiring

Oxygen sensor:

• Oxygen sensors are used to monitor and adjust the air fuel mixture. If a problem exists in this monitoring system, it will affect the PCM’s calculations for air fuel ratio. This can lead to all sorts of interesting results.
• Exhaust leaks. Oxygen sensors are installed in the exhaust system. Exhaust leaks actually suck in oxygen and taint the O2 sensors readings.

Often there are unique problems with specific makes and models. For information such as this, a mechanic will resort to checking TSB’s (Technical Service Bulletins), resources such as IATN (International Automotive Technicians Network or Identifix. All three are good resources where a mechanic can call on the collective experience of other technicians.

How serious is the P2190 code?

If only this code is present, it isn’t usually an immediate problem, but it is an indicator of problems to come. If nothing is done to address this code, more obvious symptoms will eventually result.

If this code were present on a vehicle such as a police car, it would be more of a problem. Police cars tend to idle for extended periods. If a condition exists that sets this code, the vehicle will likely begin to misfire the longer it idles. Most of the time the misfire would clear up once moving, but it may not.

What repairs can fix the P2190 code?

Tune-up:

• Replace spark plugs
• Replace ignition wires
• Replace the cap and rotor if present
• Wiring harness repair to the affected coil or coils

Fuel injector replacement:

• Fuel injector connector repair or replace
• Wiring harness repair to the affected fuel injector
• Fuel injector cleaning

Fuel Pressure Regulator:

• If the regulator is vacuum controlled and the vacuum line is attached to a bank 2 intake runner

Additional comments for consideration regarding the P2190 code

Since this code indicates there is a problem on only one bank of the motor, any component that affects both banks can be ruled out. This is very helpful in narrowing down the possibilities. A technician can now ask him or herself what can affect only one bank and not both. There are only a few parts that can do this. Isolating which components are relevant at this point greatly depends on the make, model and year of the vehicle. This is where the importance of factory information becomes necessary to effectively diagnose a condition such as this.

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