How serious is this DTC?
I would say it’s a fairly minor code considering the possibilities. We’re essentially talking about a fault in a system that monitors what happens after it has already been burned and used. That said, most state/country emission standards are quite strict, so it’s a good idea to address it before it causes more harm to your vehicle, not to mention the atmosphere!
What are some of the symptoms of the code?
Symptoms of a P203E diagnostic code may include:
- Incorrect DEF (Diesel Exhaust Fluid) level reading
- Exhaust emissions out of specifications
- Check Engine Light (CEL) illuminated
- Excessive smoke
- “Low” or other DEF warning on the instrument cluster
What are some common causes of the code?
Causes of this P203E engine code may include:
- Faulty reductant level sensor
- Incorrect fluid in the DEF storage tank
- Broken wire or harness causing intermittent electrical connections
- Electrical short circuit
What are the diagnostic and troubleshooting steps for P203E?
The first step in the troubleshooting process for any malfunction is to check Technical Service Bulletins (TSBs) for known issues with the specific vehicle.
Advanced diagnostic steps become very vehicle-specific and may require the appropriate advanced equipment and knowledge to operate accurately. We include the basic steps below but refer to a repair guide specific to the year/make/model/drivetrain for steps tailored to your vehicle.
Basic Step #1
Ensure to completely clear all active codes and test drive the vehicle before diagnosing the present codes. This will clear any codes that were left active after repairs or other intermittent and less significant codes. After a road test, re-scan the vehicle and proceed with diagnosing only the active codes.
Basic Step #2
I’m sure after owning your vehicle for a significant period, you know where the DEF (Diesel Exhaust Fluid) storage tank is located. If not, I’ve seen them located in the trunk and also under the vehicle. That said, the storage tank’s fill neck should be easily accessible, either in the trunk or next to your fuel fill neck. Make sure to distinguish it first and foremost to avoid putting unwanted fluid in unwanted places. If you can check your level mechanically with a dipstick, go ahead and do so. Some vehicles, on the other hand, have no way to check the DEF level other than aiming a flashlight into the hole to visually see if there’s DEF inside. In any case, you’ll want to top off the fluid, especially if P203F is present.
Basic Step #3
Depending on your OBD2 code reader/scan tool’s capabilities, you may be able to monitor the sensor electronically with it. Especially if you know the storage tank is full of DEF and the reading demonstrates otherwise. If that’s the case, the reductant level sensor is likely faulty and will need replacement. This can be tricky given that it will be mounted on the tank. Be sure to catch any DEF that comes out when replacing the sensor.
Basic Step #4
If you can easily access the reductant level sensor connector, ensure it’s making a good electrical connection. Also, it’s always wise to refer to the manufacturer’s service data for specific values and level sensor testing procedures to confirm it’s faulty before replacing it. You’ll likely need a multimeter for this as there might be resistance tests involved. Compare the actual present values to the desired ones provided by the manufacturer. If the values are out of specification, the sensor will need to be replaced.
NOTE: Always follow the manufacturer’s guidelines for when to disconnect your battery, safety precautions, etc.
Basic Step #5
Inspect the reductant level sensor wiring harness for any damage or chafed wires; this can cause erratic values to be sent to the ECM and lead you to replace the sensor when it wasn’t necessary. Any exposed wire or corrosion should be repaired before continuing. Ensure the harness is securely fastened and away from all moving parts.
This article is strictly for informational purposes only, and the technical data and service bulletins for your specific vehicle should always take precedence.