Reductant Level Sensor Circuit Range/Performance, Possible Adblue Problem

[CTurner]

Hi everyone, I wonder if anyone can help please. We seem to be having some of the dreaded adblue problems on our T6.

After the 550 mile warning we topped up the adblue in the middle of the recommended amount with 10ltrs. It didn’t register so took it for multiply drives and finally it jumped up to 5500, great.

Then after a few more drives the EML came on and the adblue reading went down to 5000. We didn’t do 500 miles, more like 100.

The EML code we get is P203B00 reductant level sensor circuit range/performance. Is this code linked to the adblue system or would it be something different? Does anyone have a suggestion for a fix for this please?

Thanks so much.

 

[manfrotto]

Did you clear the code? It may be stored from when you topped it up, if it didn't register the top up correctly - You need to let it register the top up before starting the engine.

 

[mmi]

5500, great.

Then after a few more drives the EML came on and the adblue reading went down to 5000. We didn’t do 500 miles, more like 100.

That's normal as the range is shown in 500 mile chunks. So e.g. if the actual readings were 5050 miles (rounded up as 5500 for dash) and after 100 miles actual was 4950 miles (rounded up for dash display as 5000).

The EML code we get is P203B00 reductant level sensor circuit range/performance. Is this code linked to the adblue system

Yes, it's about AdBlue system.
The actual explanation for the code is

P203B 00 - Reductant Level Sensor - Implausible Signal

So would be more than helpful to know what kind of implausibility there was - the engine control unit have recorded relevant data what it was expecting and what it received when the fault happened. What's the AdBlue level seen by the sensor?
Rodents damaged the wiring?

 

[CTurner]

Did you clear the code? It may be stored from when you topped it up, if it didn't register the top up correctly - You need to let it register the top up before starting the engine.

Yes we had cleared the code and it was gone when it finally registered but has now come back when the reading went down to 5000.

 

[CTurner]

That's normal as the range is shown in 500 mile chunks. So e.g. if the actual readings were 5050 miles (rounded up as 5500 for dash) and after 100 miles actual was 4950 miles (rounded up for dash display as 5000).


Yes, it's about AdBlue system.
The actual explanation for the code is

P203B 00 - Reductant Level Sensor - Implausible Signal

So would be more than helpful to know what kind of implausibility there was - the engine control unit have recorded relevant data what it was expecting and what it received when the fault happened. What's the AdBlue level seen by the sensor?
Rodents damaged the wiring?

Thanks for this, that’s helpful to know. We have a Carista and it’s given this info:

P203B00 - Reductant Level Sensor Circuit Range/Performance

Freeze frame :
Priority: 2
Malfunction frequency counter: 2
Unlearning counter: 255
Odometer reading: 80326.5 miles
Engine rpm: 1128.25 RPM
Normed load value: 0 %
Vehicle speed: 21.7 mph
Coolant temperature: 90 °C
Intake air temperature: 19 °C
Ambient air pressure: 14.36 PSI
Voltage terminal 30: 14.406 V

I’m not sure what any of this means though.

We have reset it again and hoping it won’t happen again. We are going camping in France soon so don’t want to risk any issues over there.

 

[mmi]

P203B00 - Reductant Level Sensor Circuit Range/Performance

Freeze frame :
Priority: 2
Malfunction frequency counter: 2
Unlearning counter: 255
Odometer reading: 80326.5 miles
Engine rpm: 1128.25 RPM
Normed load value: 0 %
Vehicle speed: 21.7 mph
Coolant temperature: 90 °C
Intake air temperature: 19 °C
Ambient air pressure: 14.36 PSI
Voltage terminal 30: 14.406 V

Are you sure that's all - perhaps scroll further down, or on a second page? Or just a shortcoming of Carista - as the number of recorded data items varies on different faults? It seems that Carista shows only the basic/common data of any fault?

As below what VCDS captures when reading all freeze frame data - including the implausible fill level.

22585 - Reductant Level Sensor
          P203B 00 [237] - Implausible Signal
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 74700 km
                    Date: 2022.09.18
                    Time: 17:17:20

                    Engine RPM: 2189.00 /min
                    Normed load value: 34.9 %
                    Vehicle speed: 43 km/h
                    Coolant temperature: 91 °C
                    Intake air temperature: 100 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 12.540 V
                    Unlearning counter according OBD: 40
                    Outside temperature sensor 1: B1: raw value: 22.0 °C
                    Reducing agent pump module relative press.: calculated: 7175 hPa
                    Reducing agent fill level sensor: act. value: 0.0 mm
                    Sensor for reducing agent tank temperature: temperature: 22.1 °C
                    Reducing agent system pressurization release conditions-Bits 0-7: 0
                    Reducing agent system pressurization release conditions-Bits 0-7: 0
                    Reducing agent system: current status: COSCR_PRESSURECTL
                    Reducing agent system: current status-Test_Program_SCR Con State 01 UBYTE: 4

 

[CTurner]

Are you sure that's all - perhaps scroll further down, or on a second page? Or just a shortcoming of Carista - as the number of recorded data items varies on different faults? It seems that Carista shows only the basic/common data of any fault?

As below what VCDS captures when reading all freeze frame data - including the implausible fill level.

22585 - Reductant Level Sensor
          P203B 00 [237] - Implausible Signal
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 74700 km
                    Date: 2022.09.18
                    Time: 17:17:20

                    Engine RPM: 2189.00 /min
                    Normed load value: 34.9 %
                    Vehicle speed: 43 km/h
                    Coolant temperature: 91 °C
                    Intake air temperature: 100 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 12.540 V
                    Unlearning counter according OBD: 40
                    Outside temperature sensor 1: B1: raw value: 22.0 °C
                    Reducing agent pump module relative press.: calculated: 7175 hPa
                    Reducing agent fill level sensor: act. value: 0.0 mm
                    Sensor for reducing agent tank temperature: temperature: 22.1 °C
                    Reducing agent system pressurization release conditions-Bits 0-7: 0
                    Reducing agent system pressurization release conditions-Bits 0-7: 0
                    Reducing agent system: current status: COSCR_PRESSURECTL
                    Reducing agent system: current status-Test_Program_SCR Con State 01 UBYTE: 4

I think the Carista is very limited on the details. We have cleared the error and have a 600mile trip this weekend so we will keep an eye on things and hopefully the light doesn't come back on.
Thanks for your help