How severe is this DTC?
Most of the time, I would say that emission-related codes are fairly low on the severity scale. Especially when compared to some potential dangers in other vehicle systems like steering, suspension, brakes, etc. The point here is that if you have bigger fish to fry, so to speak, you can put it on the back burner for now. That said, any electrical fault should be treated with a certain sense of urgency.
What are some of the symptoms of the code?
Symptoms of a P2203 fault code may include:
- Increased hydrocarbon emissions
- Check engine light on
- Inconsistent fuel economy
- Rough idle
- Excessive smoke
What are some common causes of the code?
Causes
of this P2203 fuel compensation code may include:
- Faulty or damaged NOx sensor
- Dirty sensor
- Damaged wiring
- Internal ECM problem
- Connector issue
What are the troubleshooting steps for P2203?
Visually inspect your sensor and harness. Sometimes, the elements we expose our vehicles to are the very reason for your fault. I’ve seen rocks, curbs, snow, and ice remove sensors like these, so make sure the sensor is intact and looks good. Keep in mind that some of these harnesses may be routed in close proximity to the exhaust, so it’s possible for wires to be burned/melted and cause all sorts of problems.
TIP: Let the engine cool down before working near the exhaust.
Clean the sensor. Ensure that any sensor mounted in the exhaust goes through countless heating and cooling cycles. Therefore, they expand and contract enough to sometimes become seized in the sensor “bung” (threaded hole) on the exhaust.
If that’s the case, you may need to apply heat to the threads, NOT directly to the sensor, as you risk damaging the NOx sensor that way. If you’ve never applied heat to help break free nuts or bolts, I advise against starting with this. That being said, if you have any doubts about your skills/abilities, you should always take your vehicle to a reputable service station.