P21B0
DTC P203B-P203D, P21AA, P21AB, P21AF, or P21B0
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P203B
- Reductant Level Sensor Performance
DTC P203C
- Reductant Level Sensor 1 Circuit Low Voltage
DTC P203D
- Reductant Level Sensor 1 Circuit High Voltage
DTC P21AA
- Reductant Level Sensor 2 Circuit Low Voltage
DTC P21AB
- Reductant Level Sensor 2 Circuit High Voltage
DTC P21AF
- Reductant Level Sensor 3 Circuit Low Voltage
DTC P21B0
- Reductant Level Sensor 3 Circuit High Voltage
Circuit/System Description
The reductant level/temperature sensor is a solid-state device that provides the engine control module (ECM) with information on reductant level and temperature. The level/temperature sensor receives system voltage directly from the underhood electrical center and ground through a chassis ground circuit. The level sensor consists of three sensing elements. Reductant level sensor 3 is highest, reductant level sensor 2 is located between sensor 1 and 3. Reductant level sensor 1 is located at low reductant level. Reductant level sensor 3 is located at less than half range of the DEF tank level. The scan tool will display Active when the level sensors are in contact with reductant and Inactive when not in contact with reductant. An integrated temperature sensor monitors reductant temperature. Reductant level and temperature signals are processed within the sensor and supplied to the ECM as serial data messages. The ECM will set a DTC when it detects an invalid level or temperature serial data message from the sensor.
Conditions for Running the DTC
* The engine speed is greater than 600 RPM.
* The battery voltage is greater than 11 V.
* The ambient air and emission reduction fluid tank temperatures are warmer than -7°C (19°F) - DTC P203B only.
* The engine run time is greater than 10 s.
* The DTCs run continuously once the above conditions are met.
Conditions for Setting the DTC
P203B
The ECM receives a serial data message from the Reductant Sensor Module that the reductant level sensor indications are not plausible.
P203C, P21AA, and P21AF
The ECM receives a serial data message from the Reductant Sensor Module that the emission reduction fluid tank level sensor 1, 2 or 3 voltage is less than 0.17 V for greater than 3 s. A voltage within this range indicates a short to ground.
P203D, P21AB, and P21B0
* The ECM receives a serial data message from the Reductant Sensor Module that the emission reduction fluid tank level sensor 1, 2 or 3 voltage is between 3.56-4.74 V for greater than 3 s. A voltage within this range indicates an open circuit.
Or
* The ECM receives a serial data message from the Reductant Sensor Module that the emission reduction fluid tank level sensor 1, 2 or 3 voltage is greater than 4.74 V for greater than 3 s. A voltage within this range indicates a short to voltage.
Action Taken When the DTC Sets
DTCs P203B, P203C, P203D, P21AA, P21AB, P21AF, and P21B0 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P203B, P203C, P203D, P21AA, P21AB, P21AF, and P21B0 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
* Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Level) (Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Level)) Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Quality) (Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Quality)) Diesel Exhaust Fluid (DEF) Warning Strategy (Anti-Tampering) (Diesel Exhaust Fluid (DEF) Warning Strategy (Anti-Tampering))
* Exhaust Aftertreatment System Description (Emission Control Systems)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine idling, observe the scan tool DTC information. DTC P203B should not be set.
• If a DTC is set, replace the emission reduction fluid tank.
2. Ignition ON, observe the circuit status parameters listed below with a scan tool:
* Reductant Lvl Sen 1 Circuit Status
* Reductant Lvl Sen 2 Circuit Status
* Reductant Lvl Sen 3 Circuit Status
Each parameter should display OK or Incomplete
• If not the specified value, replace the emission reduction fluid tank.
3. Operate the vehicle within the Conditions for Running the DTC, to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Fame/Failure Records Data List.
Repair Instructions
* Emission Reduction Fluid Tank Replacement (Emission Reduction Fluid Tank Replacement)
* Perform the scan tool Reductant System Reset procedure after replacing the emission reduction fluid tank.
Repair Verification
1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
3. Clear the DTCs.
4. Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes.
Note: The diesel exhaust fluid (DEF) and ambient air temperatures must be greater than -7°C (19°F) before proceeding with this procedure.
5. Ignition ON, command the Reductant System Leak Test ON with a scan tool. Allow the pressure to build for 30 s. Observe the scan tool Reductant Pressure sensor parameter. The reading should be between 425-575 kPa and there should be no leaks in the system.
Warning
Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.
6. Engine idling at operating temperature. Accelerate at part throttle to 32-48 km/h (20-30 mph) for up to 5 minutes or until the DEF lamp turns OFF. The DEF lamp should turn OFF.
• If the DEF lamp does not turn OFF, a condition with the system still exists.