P220D

Code

Generic P — Powertrain

NOx Sensor Supply Voltage Circuit Bank 2 Sensor 2

Brand: Generic

Type: P — Powertrain

Views: UK: 28 EN: 44 RU: 29

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Read DTC and capture freeze-frame and live data with a scan tool (monitor NOx sensor supply voltage and related parameters)
Check for other stored codes that could be related (fuses, powertrain, CAN/communication)
Perform a visual inspection of the sensor, connector, and wiring harness for damage, heat, soot, or water intrusion
Verify fuses and relays that supply the NOx sensor/heater (replace if faulty)
Backprobe the sensor supply pin with a digital multimeter (key ON/engine OFF) and note voltage vs. spec
With engine running (if safe), monitor supply voltage and observe for drops or intermittent behavior while gently wiggling wiring and connectors

Expected supply (heater) ≈ battery voltage with ignition ON/run (typical 11–14 V) — verify exact spec in service manual
Open circuit = infinite/OL; short to ground ≈ 0 V; short to battery ≈ battery voltage on supply pin
Heater resistance typical range varies by sensor (commonly low single- to double-digit ohms) — check manufacturer spec
Sensor signal/reference (non-heater) may be a low-voltage signal or CAN-reported value depending on vehicle — consult wiring diagram and specs

Use a scan tool: record freeze-frame, pending/continuous status, and live data for NOx bank 2 sensor 2. Note when the code set (ignition/run conditions).
Clear the code and perform a key-on/key-off or drive cycle to see if the code returns and under what conditions.
Visually inspect harness and connector at sensor and along routing for heat damage, chafing, corrosion, or water intrusion. Repair or protect as needed.
Check related fuses and relays for the sensor/heater circuit; replace any blown/defective items.
Backprobe the sensor supply pin at the connector with key ON (engine OFF) and measure voltage. Compare to battery voltage and service spec.
With engine running (if applicable and safe), monitor supply voltage while performing a wiggle test on harness and connector to detect intermittent faults.
Measure heater resistance at the sensor (unplug harness) and compare to spec. Replace sensor if heater open or out-of-spec.
Check continuity/resistance between the sensor supply pin and the PCM pin; check for shorts to ground or battery along the harness.
If wiring and sensor test good, inspect PCM connector and grounds; consider PCM supply driver failure if wiring/sensor are good.
After repairs, clear codes and perform verification drive cycles and re-scan to ensure the fault does not return.