The P2202 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the NOx sensor circuit for Bank 1 Sensor 1. This usually means the sensor, its wiring, or the associated power/ground circuits are not functioning as expected. When this code is set the Check Engine Light is illuminated and the vehicle may experience altered engine performance or increased emissions.
The sensor's internal heater or sensing element can fail, causing the circuit to read low voltage. This is the most common reason for P2202.
Corroded, broken, or loose wires and connectors in the sensor circuit can create an open or short, leading to low voltage readings.
A blown fuse or faulty relay that supplies power to the sensor heater can interrupt the circuit, triggering the code.
Inadequate ground connection or incorrect reference voltage can cause the sensor circuit to report low voltage.
An exhaust leak close to the NOx sensor can introduce ambient air into the exhaust stream, affecting sensor operation and circuit values.
The engine control module itself can have an internal circuit failure affecting sensor readings, but this is far less common than the above causes.
Yes, you can usually drive the vehicle, but the code should be repaired before an emissions test to avoid failing and to prevent possible performance issues.
Rarely. In most cases the problem is the sensor, wiring, or a fuse. PCM failure is an uncommon cause of P2202.
If you have basic mechanical skill and access to the sensor, you can replace it, but it’s advisable to first verify that the wiring and power supply are healthy to avoid repeating the problem.
Repairing the sensor will bring NOx readings within normal range, which is necessary for most emissions tests, but overall pass/fail depends on the complete emissions system.