Damaged or corroded wiring harness or connector at the NOx sensor.; Open circuit in the supply voltage wire between the PCM and sensor.; Short to ground or short to voltage on the supply circuit.; Failed NOx sensor with an internal short or open in its supply circuit.; Loose or poor ground connection for the sensor or PCM.; PCM driver circuit failure, though less common.; Aftermarket or incorrect sensor installed that does not meet voltage specifications.

DTC codes / P22xx · Fuel and air metering (injector circuits) / P220D

P220DNOx Sensor Supply Voltage Circuit (Bank 2 Sensor 2)

Q: What does code P220D mean?

NOx Sensor Supply Voltage Circuit (Bank 2 Sensor 2). P220D indicates that the powertrain control module (PCM) has detected an abnormal voltage on the supply circuit for the downstream nitrogen oxide (NOx) sensor on bank 2. The PCM monitors the voltage feed to the sensor and sets this code when the signal falls outside the expected range, typically because of an open, short, or excessive resistance in the wiring or connector.

P220D indicates that the powertrain control module (PCM) has detected an abnormal voltage on the supply circuit for the downstream nitrogen oxide (NOx) sensor on bank 2. The PCM monitors the voltage feed to the sensor and sets this code when the signal falls outside the expected range, typically because of an open, short, or excessive resistance in the wiring or connector.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms.
Reduced engine performance or power, as the PCM may limit torque to protect emissions components.
Decreased fuel efficiency due to altered fuel injection strategies.
Possible rough idle or hesitation if the fault affects other sensor readings.
In some vehicles, a message indicating emissions system service required.
Intermittent warning light if the circuit fault is temperature or vibration sensitive.

Common causes, most likely first

Damaged or corroded wiring harness or connector at the NOx sensor.
Open circuit in the supply voltage wire between the PCM and sensor.
Short to ground or short to voltage on the supply circuit.
Failed NOx sensor with an internal short or open in its supply circuit.
Loose or poor ground connection for the sensor or PCM.
PCM driver circuit failure, though less common.
Aftermarket or incorrect sensor installed that does not meet voltage specifications.

How to diagnose and fix it

Inspect the NOx sensor connector and wiring for damage, corrosion, or loose pins; repair as needed.
Check the supply voltage at the sensor connector with the key on and compare to manufacturer specification.
Measure resistance of the supply wire from the PCM to the sensor to detect opens or high resistance.
Test for shorts to ground or voltage on the supply circuit with a multimeter.
Verify the sensor ground circuit integrity and clean or tighten ground connections.
If wiring and connections are good, substitute a known-good NOx sensor and clear the code.
If the code persists after sensor replacement, diagnose the PCM driver circuit or reprogram/replace the PCM as directed by service information.

Don't overlook the supply circuit

A common mistake is replacing the NOx sensor without first checking the supply voltage and ground, as a simple chafed wire often causes this code.
The code can be set by a weak battery or charging system issue that causes low voltage to the sensor during cranking or heavy load.
Some vehicles require a relearn or adaptation reset after NOx sensor replacement, and skipping this step may cause the code to return.
Bank 2 Sensor 2 refers to the downstream sensor on the bank that does not contain cylinder 1; misidentifying the bank can lead to replacing the wrong sensor.
Corrosion inside the connector pins can create resistance that only appears under vibration or temperature change, so wiggle-test the harness while monitoring voltage.

Can I keep driving with P220D?

You can generally drive the vehicle with this code, but avoid heavy loads and long trips until repaired, as continued driving may increase emissions and lead to reduced performance or further component damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.