The error code 21 for a 1995 Chrysler Cirrus means that the Oxygen Sensor Circuit Bank 1 Sensor 1 is not functioning properly. This oxygen sensor is located in the exhaust manifold, and it measures the amount of oxygen in the exhaust gas. The data about oxygen levels is shared with the engine control unit (ECU), which then adjusts the air-fuel mixture accordingly. If the oxygen sensor is not working properly, the ECU cannot make the necessary adjustments and the engine may run rich or lean. This can cause a number of problems, including decreased fuel economy, increased emissions, and poor engine performance.
To fix the error code 21, you will need to replace the oxygen sensor. The oxygen sensor is a relatively inexpensive part, and it is easy to replace. You can do it yourself with a few simple tools.
