Troubleshooting DTC P2224: Decryption, Causes, Reset

Trouble code P2224 sounds like “Nitrogen Oxide Sensor Heater Circuit High (Bank 2)”. Often, in programs that work with an OBD-2 scanner, the name may have the English spelling “Nitrogen Oxides (NOx) Sensor Heater Sense Circuit High (Bank 2)”.

Technical description and interpretation of error P2224

DTC P2224 is a generic DTC that is defined as a high signal on the NOx sensor heater circuit (Bank 2). Set when the powertrain control module (PCM) detects a high signal in the NOx sensor heater itself or its circuit.

The PCM uses NOx sensors to monitor the level of nitrogen oxide in the exhaust to get an idea of ​​the amount of hydrocarbons being emitted. Since NOx is one of the main pollutants that diesel engines produce.

The NOx sensor heater circuit is responsible for preheating the sensor, which is necessary to speed up the sensor warm-up time. This allows you to efficiently bring it up to operating temperature without relying solely on exhaust gas temperature to warm it up.

When the PCM detects a high voltage on the nitrogen oxide sensor heater circuit (Bank 2), it sets code P2224, which will then illuminate the warning light. The code appears when the control module detects a problem with the output level from this NOx sensor heater circuit.

If the warning light is flashing, this indicates a serious problem that may be affecting the catalytic converter.

Malfunction symptoms

The main symptom of a P2224 code for the driver is the MIL (Malfunction Indicator Lamp) light. It is also called Check engine or simply “check is on”.

They can also appear as:

  1. The control lamp “Check engine” on the control panel will light up (the code will be stored in memory as a malfunction).
  2. Increase in harmful emissions.
  3. Floating speed, as well as attempts to stall at idle.
  4. Reduced engine power.
  5. Increased fuel consumption.
  6. Excessive smoke from the exhaust pipe.
  7. The vehicle may fail the emissions test.

Error P2224 is not considered very serious, however, like any problem, it is recommended to solve it. With this code, you will most likely fail the environmental test, as emissions of harmful substances will be exceeded.

Reasons for the error

Code P2224 may mean that one or more of the following problems have occurred:

  • Faulty heater in NOx sensor.
  • Faulty or damaged NOx sensor.
  • The NOx sensor is contaminated.
  • Damaged or worn NOx sensor connector.
  • Damaged wiring.
  • Sometimes the cause is a bad PCM.

How to troubleshoot or reset DTC P2224

Some suggested steps to troubleshoot and fix error code P2224:

  1. Connect an OBD-II scanner to the vehicle’s diagnostic socket and read all stored data and error codes.
  2. Clear the error codes from the computer’s memory and test drive the vehicle to see if the P2224 code appears again.
  3. If the code reappears, check the wiring and related connectors to the NOx sensor. Make sure they are not broken or worn. Repair or replace if necessary.
  4. Inspect and test the NOx sensor, replace if necessary if it fails.
  5. If the cause is a bad PCM, replace it or reprogram it.

Diagnosis and problem solving

Inspect for visible damage to the sensor, wiring, and connectors. Then start the diagnostic procedure using the scanner. To determine if P2224 is the only one, if not, it may be worth looking into other DTCs first.

If no problems are found with damaged or corroded connectors, perform a thorough inspection of all associated wiring. Repair or replace damaged wiring as needed.

Check wiring and NOx sensor

If there is no visible damage to the wiring, prepare to perform voltage reference, ground, resistance, and continuity tests. Be sure to disconnect the sensor from the wiring harness to avoid damaging the PCM and avoiding a short circuit.

The NOx sensor is part of the control circuit and must also be tested. Compare all readings taken on the sensor with the values ​​given in the manual. Replace the sensor if the reading is outside the specified range or value.

When replacing the NOx sensor, make sure all connections are secure and that all wiring is secured away from hot components. Then start the engine and let it warm up to normal temperature so that the new sensor goes into closed loop mode.

The main cause of the P2224 code is a faulty NOx sensor, so replacing it should fix the problem.

Which vehicles are more likely to have this problem?

The problem with code P2224 can occur on various machines, but there are always statistics on which brands this error is present more often. Here is a list of some of them:

  • Audi
  • Dodge (Dodge Ram)
  • Ford
  • Honda
  • Jeep
  • Mercedes (Mercedes Sprinter)
  • Volkswagen (Volkswagen Passat)

With DTC P2224, other errors can sometimes be found. The most common are the following: P2221, P2222, P2223, P2225.

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