U02A200

DTC (Code)
Codigo:
Bulletin:
U02A2-00
RD18-002
Date Fecha: August 11, 2018
Description:
Lost Communication with Reductant Quality Module – No
additional information
Application:
US13 – US20 Emissions
General Information
These repair instructions are intended to address the following faults:
DTC
Description
U02A2-00
Lost Communication
with Reductant Quality
Module
Possible
(Observable)
Symptoms
Possible Cause
•
•
•
The electronic control unit (ECU) has a software fault
or the wrong software version
Control unit has no supply voltage
Connector
None
Required Parts
Part Number
Description
Quantity
21073825
DEF Level Sensor
1
Repair Instructions
Aftertreatment Diesel Exhaust Fluid (DEF) Tank, Level Sensor, Replacement
Removal
1. Secure the vehicle for service by parking it on a flat level surface, applying the parking brake, chocking the
rear wheels, and placing the transmission in neutral or park.
2. Disable battery power.
3. Move the engine control switch on the rear control panel to the "OFF" position.
4. Close all the coolant valves to the bus interior. Connect the coolant extractor and drain the engine coolant.
Special tools: 85112740 Note: On B13R buses, the panel under the coolant package must be removed to
access the coolant extractor fitting.
5. Place a suitable container under the DEF tank to catch any spilled DEF and coolant during the removal
procedure. Note: On B13R buses, the panel under the DEF tank must be removed to access the drain on the
DEF tank.
© 2016 Information is subject to change without notice.
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DTC (Code)
Codigo:
U02A2-00
Bulletin:
RD18-002
Date Fecha: August 11, 2018
6. Remove the drain plug from the DEF tank and drain fluid in the DEF tank into the container. When all the fluid
has drained from the DEF tank, replace the drain plug and tighten. Discard the used DEF according to local
regulations.
1. DEF Tank Drain Plug
7. Disconnect the wiring harness from the DEF tank level sensor.Note: Cover the wiring harness connectors with
a plastic bag to protect them from any spilled DEF which is highly corrosive to electrical contacts.
8. If equipped, disconnect the electrical harness from the DEF quality sensor module. Remove the fasteners from
the module. Note: Cover the wiring harness connectors with a plastic bag to protect them from any spilled DEF
which is highly corrosive to electrical contacts.
1. DEF Quality Sensor Module Electrical Connector
© 2016 Information is subject to change without notice.
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DTC (Code)
Codigo:
U02A2-00
Bulletin:
RD18-002
Date Fecha: August 11, 2018
9. Disconnect the DEF lines from the DEF tank level sensor fittings.
1. DEF Lines
10. Disconnect the two coolant lines from the fittings on the DEF tank level sensor.
1. Coolant Line
2. Coolant Line
© 2016 Information is subject to change without notice.
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DTC (Code)
Codigo:
U02A2-00
Bulletin:
RD18-002
Date Fecha: August 11, 2018
11. Remove the fasteners securing the DEF tank to the vehicle chassis and carefully remove the tank from the
vehicle compartment. Note: On Prevost X models, the DEF pump must be moved to allow tank removal.
1. Mounting Fasteners
12. Loosen the clamp securing the DEF level sensor in the DEF tank and remove the level sensor and quality
sensor module, if equipped. Use care when handling the sensor to avoid damaging the sensor.
1. DEF Level Sensor
© 2016 Information is subject to change without notice.
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DTC (Code)
Codigo:
U02A2-00
Bulletin:
RD18-002
Date Fecha: August 11, 2018
Installation
1. Check DEF tank for debris. Flush tank if necessary.
2. Position the level sensor in the DEF tank and tighten the clamp to secure it in place. Use care when handling
the sensor to avoid damaging the sensor.
1. DEF Level Sensor
3. Position the DEF tank in the vehicle compartment and use the fasteners to secure it in place on the chassis.
Tighten the fasteners to specification; refer to Function Group 20, Specifications. Note: On Prevost X models,
the DEF pump must be reinstalled.
1. Mounting Fasteners
4. Remove the protective plastic bag from the wiring harness connector and connect the wiring harness lead to
the level sensor connector.
© 2016 Information is subject to change without notice.
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DTC (Code)
Codigo:
U02A2-00
Bulletin:
RD18-002
Date Fecha: August 11, 2018
5. If equipped, position the DEF quality sensor module and install fasteners. Remove the protective plastic bag
from the wiring harness connector and connect electrical harness to the DEF quality sensor module electrical
connector.
1. DEF Quality Sensor Module Electrical Connector
6. Attach the two coolant lines to the fittings on the DEF tank level sensor.
Coolant Line
Coolant Line
7. Fill the DEF tank with new DEF fluid.
8. Reinstall the engine coolant using the coolant extractor. Open all coolant valves to the bus interior. Special
tools: 85112740
9. Turn the battery switch to "ON".
© 2016 Information is subject to change without notice.
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DTC (Code)
Codigo:
Bulletin:
U02A2-00
RD18-002
Date Fecha: August 11, 2018
Additional Resources
These repairs are the most likely fix for the identified fault(s), if this does not fix the issue, Tech Tool will need to be
used for more detailed diagnostics. If filing a warranty claim, please include the ASIST case number.
Labor Code
2589-03-02-05
2.4
Causal Part
21073825
© 2016 Information is subject to change without notice.
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