Internal combustion engines require a precise air-to-fuel ratio when they’re mixed in the cylinders before combustion. The rule of thumb is that there be 14.7 parts of air to only 1 part of fuel. This is referred to as the 14.7:1 air-to-fuel ratio, and it is the standard for most gasoline engines.
There are several components of the fuel system which work together to ensure this ratio is maintained. The oxygen sensor is one of those components because it detects whenever there is under 14.7 parts of air in the cylinders. Once it is detected, the oxygen sensor transmits this information back to the powertrain control module. To handle the problem, the module will cause the fuel injectors to put less fuel into the cylinders in order to keep the ratio maintained.
Less air in the cylinders means the air-to-fuel ratio has a rich mixture. In other words, there is more fuel in the cylinders in proportion to the amount of air in them. So, the powertrain control module tries to reduce the fuel in order to keep the proportions balanced. However, this is a recipe for disaster because the engine will eventually suffer internal damage. The catalytic converter may fail too.
Trouble Code P0172 will be generated by the powertrain control module when the oxygen sensor detects less oxygen in Bank 1. This means that Bank 1 has a rich condition. You’ll know when this problem exists because you’ll have a rough idling engine, weak acceleration power, engine misfires, engine hesitation, fuel odor from the exhaust, and a Check Engine warning light. These should be enough symptoms to want to solve the problem.
Your first instinct may be to assume the oxygen sensor or air-to-fuel ratio sensor is bad. Although they could be the problem, there are other possible causes of the rich condition in Bank 1. There could be a bad mass airflow sensor, leaky fuel injectors, bad spark plugs, bad coolant temperature sensor, bad fuel pressure regulator, bad coolant temperature sensor, or bad coolant thermostat.
- P0404: Exhaust Gas Recirculation Circuit Range/Performance
- P1404: Exhaust Gas Recirculation Closed Position Performance
As for your driving, you can survive for a short time but don’t take too long. Get the problem fixed soon before your engine components suffer any further damage.