P2220 OBD-II Trouble Code: NOx Sensor Heater Control Circuit High Bank 2

P2220 code definition

NOx Sensor Heater Control Circuit High Bank 2

What the P2220 code means

P2220 is an OBD-II code for the engine control module (ECM) detecting the NOx sensor heater control circuit has a high voltage reading for bank 2 of the engine.

What causes the P2220 code?

  • The engine control module (ECM) monitors the NOx heater control circuit. The ECM detected the NOx heater circuit voltage is high indicating a short in the NOx sensor heater circuit.

  • The bank 2 of the engine cannot go into closed loop fast enough and will cause the sensor to have a slow response signal until it gets heated up by the exhaust and not the heater circuit.

What are the symptoms of the P2220 code?

  • The Check Engine Light will be illuminated and the code is set in ECM memory as a fault.

  • The engine may run lean on bank two and the engine may run rough and misfire.

  • The ECM may go into open loop and possible failure mode depending on the failure strategy of the computer programming.

How does a mechanic diagnose the P2220 code?

  • Scan for codes and document the code in the ECM and look at the freeze frame data for failure

  • Monitor the NOx sensor for bank 2 heater control circuit and compare to sensor for bank 1

  • Check the O2 sensor and wiring for physical damages

  • Follow the manufacturer pinpoint tests for the diagnosis and replacement of the NOx sensor on bank 2 sensor 1.

Common mistakes when diagnosing the P2220 code?

  • Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired

  • Failing to clear the ECM codes after the codes are fixed so the ECM will enable the system to operate normal again

  • Failing to check the harness for shorts in the harness or connector

How serious is the P2220 code?

Code P2220 is a code indicating the engine NOx sensor heater circuit is shorted out and may cause the engine to emit excessive NOx gas and fail emissions. High NOx could mean the engine is running too lean.

What repairs can fix the P2220 code?

  • Repairing a melted harness and connector
  • Replacing the NOx sensor for bank two
  • Rechecking the system to make sure it goes into closed loop and the NOx sensors are reading correctly

Additional comments for consideration regarding the P2220 code

Code P2220 is for a shorted NOx sensor on bank 2 heater circuit, and the most common failure is the sensor being damaged physically or oil soaking and causing an internal short on the sensor heater wires. High NOx means the engine is running too lean and can damage pistons and head chambers or valves.

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