The P2225 error code reads Nitrogen Oxide Sensor Heater Circuit Intermittent (Bank 2). Often, in programs working with an OBD-2 scanner, the name may have the English spelling “Nitrogen Oxides (NOx) Sensor Heater Sense Circuit Intermittent (Bank 2)”.
P2225 datasheet and explanation
DTC P2225 is generic and is defined as an intermittent signal in the NOx sensor heater circuit (Bank 2). Set when the powertrain control module (PCM) detects an intermittent signal in the NOx sensor heater itself or in 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 emitted. Since NOx is one of the main pollutants that diesel engines produce.
The NOx sensor heater circuit is responsible for preheating the sensor to speed up the sensor warm-up time. This allows it to be brought to operating temperature efficiently without relying solely on the exhaust gas temperature to warm it up.
When the PCM detects an intermittent signal on the NOx sensor heater circuit (Bank 2), it sets code P2225 and the warning light comes on. 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, it indicates a serious problem that may be affecting the catalytic converter.
The primary driver symptom of a P2225 code is a MIL (Malfunction Indicator Light) illuminated. It is also called Check engine or simply “check is on”.
They can also manifest as:
- The control lamp “Check engine” on the control panel will light up (the code will be written into memory as a malfunction).
- Increase in harmful emissions.
- Floating revs, as well as attempts to stall at idle.
- Decreased engine power.
- Increased fuel consumption.
- Excessive smoke from the exhaust pipe.
- The vehicle may not pass the emission test.
The P2225 code is not considered a very serious code, however, like any problem, it is recommended that you fix it. With this code, you most likely will not pass the environmental test, as the emissions of harmful substances will be exceeded.
Reasons for the error
A P2225 code may indicate one or more of the following problems have occurred:
- Malfunction of the heater in the NOx sensor.
- Defective or damaged NOx sensor.
- The NOx sensor is dirty.
- Damaged or worn NOx sensor connector.
- Damaged wiring.
- Sometimes the cause is a faulty PCM.
How to Repair or Reset DTC P2225
Some suggested steps to troubleshoot and fix the P2225 error code:
- Connect the OBD-II scanner to the vehicle diagnostic socket and read all stored data and error codes.
- Clear the error codes from the computer memory and test drive the vehicle to see if the P2225 code appears again.
- If the code reappears, check the wiring and associated connectors to the NOx sensor. Make sure they are not broken or worn out. Repair or replace as necessary.
- Inspect and test the NOx sensor, replace if necessary if damaged.
- If the cause is a faulty PCM, replace or reprogram it.
Diagnostics and problem solving
Inspect for any visible damage to the sensor, wiring, and connectors. Then start the diagnostic procedure using the scanner. To determine if the P2225 code is the only one, if not, it may be worth dealing with other DTCs first.
If no problem is found with damaged or corroded connectors, perform a thorough inspection of all associated wiring. Repair or replace damaged wiring as needed.
Checking the wiring and NOx sensor
If no visible damage to the wiring is found, prepare to perform reference voltage, grounding, 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 from the sensor to 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 for the new sensor to go into closed loop mode.
The root cause of the P2225 code is a faulty NOx sensor, so replacing it should fix the problem.
On what cars is this problem more common?
The problem with the P2225 code can occur on different machines, but there are always statistics on which brands this error is more common. Here is a list of some of them:
- Mercedes (Mercedes Vito, Sprinter)
Other errors can sometimes be found with DTC P2225. The most common are the following: P2221, P2222, P2223, P2224.