P203F Reductant level too low

OBD-II Trouble Code - P203F - Data Sheet

P203F - Reducer level too low.

What does DTC P203F mean?

This is a generic powertrain diagnostic trouble code (DTC) and is commonly applied to OBD-II vehicles. Car brands may include, but are not limited to, BMW, Mercedes Benz, VW Volkswagen, Sprinter, Ford, Audi, Dodge, Ram, GMC, Chevrolet, Jeep, etc.

Did you know that the engine light comes on when the engine exhaust emissions are out of specification? The ECM (Engine Control Module) monitors and regulates dozens of sensors, valves, systems, etc. It basically acts as a built-in emission check station. It not only monitors what your engine is consuming, but more importantly for the manufacturer, what your engine is emitting into the atmosphere.

This is relevant here because for the most part reductant level sensors are present on diesel vehicles with a DEF (diesel exhaust fluid) storage tank. DEF is a urea solution used in diesel engines to burn exhaust gases, which in turn reduces overall vehicle emissions, which, as mentioned earlier, is one of the most important goals of ECM. The reductant level sensor informs the ECM of the level of DEF in the storage tank.

P203F is a DTC defined as Reductant Level Too Low which indicates that the DEF level in the tank is too low as determined by the ECM.

Reducing agent tank DEF:

What is the severity of this DTC?

I would say that this is pretty minor code considering the possibilities. Basically, we are talking about a malfunction of a system that monitors what happens after it has already been burned and used. However, emission standards in most states / countries are quite strict, so it is advised to address this issue before it causes more damage to your vehicle, let alone the atmosphere!

What are some of the symptoms of a P203F code?

Symptoms of the P203F diagnostic code may include:

• Incorrect DEF (Diesel Exhaust Fluid) level reading
• Exhaust emissions out of specification
• CEL (check engine light) on
• Excessive smoke
• Low or other DEF warning on instrument cluster.
• There is a suspicious increase in exhaust smoke
• The DEF warning light is on your vehicle's instrument cluster.
• The DEF (Diesel Exhaust Fluid) reading is not accurate.
• Your vehicle's exhaust emissions do not meet manufacturer's specifications.

What are some of the common causes for the code?

Reasons for this P203F engine code may include:

• Reductant level sensor defective
• Wrong liquid in DEF storage tank
• DEF is low and needs to be replenished.
• Short circuit near the sensor

What are the steps to diagnose and troubleshoot a P203F?

The first step in the process of troubleshooting any problem is to review technical service bulletins (TSBs) for known problems with a particular vehicle.

Advanced diagnostic steps become very vehicle specific and may require appropriate advanced equipment and knowledge to be performed accurately. We outline the basic steps below, but refer to your vehicle / make / model / transmission repair manual for specific steps for your vehicle.

Basic step # 1

Be sure to completely erase all active codes and test drive the vehicle before diagnosing any existing codes. This will clear any codes that remained active after repairs or other periodic, less important codes. After a test drive, re-scan the vehicle and continue diagnosing only with active codes.

Basic step # 2

I am sure that after you own your vehicle for a considerable amount of time, you know where the DEF (Diesel Engine Exhaust Fluid) storage tank is. If not, then I saw them in the trunk as well as under the car. In this case, the filler neck of the storage tank should be easily accessible either in the trunk or next to the filler neck for fuel. First of all, make sure you differentiate it to avoid getting unwanted liquid into unwanted places. If you can check your level mechanically with a dipstick, do so. On the other hand, some vehicles have no other way to check the DEF level other than directing the flashlight into the hole to visually see if there is a DEF there. You will want to top up anyway, especially if P203F is present.

Basic step # 3

Depending on the capabilities of your OBD2 code scanner / scanner, you can electronically monitor the sensor using it. Especially if you know the storage tank is full of DEF and the readings show something else. In this case, it is most likely that the reductant level sensor is defective and needs to be replaced. This can be tricky considering the fact that it will be installed on a tank. When replacing a sensor, make sure you catch any DEF that comes out.

Basic step # 4

If you can easily access the reductant level sensor connector, make sure it provides a good electrical connection. In addition, it is always advisable to consult the manufacturer's service data for specific values ​​and testing procedures for a level sensor to ensure it is defective before replacing it. You will most likely need a multimeter for this, as resistance tests may be required. Compare the actual values ​​available with the manufacturer's desired values. If the values ​​are outside the specification, the sensor must be replaced.

NOTE: Always follow the manufacturer's instructions for when to disconnect the battery, precautions, etc.

Basic step # 5

Inspect the reductant level sensor wiring harness for damage or abrasion, this may send erroneous readings to the ECM and may force you to replace the sensor when not necessary. Any exposed wires or corrosion must be repaired before proceeding. Make sure the harness is secure and does not come into contact with moving parts.

This article is for informational purposes only and technical data and service bulletins for your specific vehicle should always take priority.

How to fix P203F reducing agent level too low

It is very important to correct DTC P203F. So here are a few ways you can fix this problem:

• Repair or replace DEF
• Repair or replace DEF sensor
• Repair or replace the fuel filler neck
• Repair or replace the ECM
• ECU repair or replacement
• Repair or replace discrete level sensor

You have nothing to worry about as Parts Avatar - Auto Parts Online is here to help you! We have high quality Discrete Level Sensor, ECU, DEF, Fuel Filler, ECM and more for our dear customers.

Brand specific P203F code information

• P203F Reductant level too low Audi
• P203F BMW reductant level too low
• P203F Too low signal level in the Dodge reductant level sensor circuit
• Reducing agent level too low Ford P203F
• P203F RAM Reductant Level Sensor Circuit Too Low
• P203F Volkswagen reductant level too low

What is P203F Engine Code [Quick Guide]

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NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.